Author Archives: LifeTein Peptide

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The custom peptide synthesis service and custom antibody product service company.

Cyclic peptides as broad-spectrum antiviral agents

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Cyclic peptides as broad-spectrum antiviral agent

Cyclic peptides as broad-spectrum antiviral agents

Antiviral drugs and vaccines are the most powerful tools to combat viral diseases. Most drugs and vaccines only target a single virus. However, the broad-spectrum antivirals can be used for rapid management of new or drug-resistant viral strains. Cyclized peptides and peptide analogs are excellent examples of broad-spectrum antivirals.

An artificial peptide molecule was found to neutralize a broad range of group 1 influenza A viruses, including H5N1. The peptide design was based on complementarity determining region (CDR) loops have been reported for other viral targets. The optimized peptides bind to the highly conserved stem epitope and block the low pH-induced conformational rearrangements associated with membrane fusion.

These peptidic compounds and their advantageous biological properties should accelerate development of novel small molecule and peptide-based therapeutics against influenza virus.

The linear peptide is Suc-SQLRSLEYFEWLSQ-NH2. Three cyclization strategies were used: head to tail, side chain to side chain and side chain to tail. An ornithine (Orn) side chain was fused with the carboxyl terminus of β-alanine for lactam formation.

Check here for more details: Potent peptidic fusion inhibitors of influenza virus, Science 28 Sep 2017, DOI: 10.1126/science.aan0516

Lately, more broad-spectrum antiviral agents were found to target viruses. It was found that 55 compounds can target eight different RNA and DNA viruses. Dalbavancin is a novel lipo-glycopeptide antibiotic. The lipoglycopeptide disrupts bacterial cell wall formation by binding to
the terminal d-alanyl-d-alanine peptidoglycan sequence in Gram-positive bacteria in a linear, concentration-dependent manner. The dalbavancin has effects on echovirus 1, ezetimibe against HIV1 and Zika virus.

More details: https://www.ncbi.nlm.nih.gov/pubmed/29698664

Magnetic Beads: Expert Tips and Protocols for Effective Use

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Magnetic beads

Protein Purification Using Magnetic Beads: Top Tips for Success

Magnetic bead-based protein purification offers a powerful solution for various applications like high-throughput microscale purification, pull-down/CoIP experiments, and protein-protein or protein-DNA interaction studies. Here’s why magnetic beads are the top choice: they can be coated with specific affinity ligands for antigens, antibodies, proteins, or nucleic acids. Moreover, magnetic beads are non-porous and have a defined diameter, eliminating hidden surfaces where molecules can stick, leading to reduced background, simplified purification, and streamlined washing steps. Compared to traditional bead separation methods involving agarose, sepharose, or silica beads, magnetic bead separation stands out as the quickest, cleanest, and most efficient technique.

If you’re new to working with magnetic beads, here are some essential tips to ensure success:

  1. Thorough Resuspension: Ensure uniformity across aliquots by thoroughly resuspending your magnetic beads. These nano-superparamagnetic beads are covalently coated with highly functional groups, providing increased binding capacity and better dispersion. Since magnetic beads are composed of iron oxide and can settle over time, it’s crucial to vortex and resuspend them thoroughly before use to redisperse the beads.
  2. Enhanced Washing: Minimize non-specific binding by increasing the number of washing steps. Whether you’re using ethanol or the recommended wash buffer, make sure to use an adequate volume of wash solution to cover the bead pellet.
  3. Understanding Functional Groups: Different beads are covalently coated with various functional groups like maleimide, primary amine, NHS, carboxylic acid, purified streptavidin, protein A, reduced glutathione, nickel-charged nitrilotriacetic acid, or groups for DNA/RNA purification. These coatings, along with buffer conditions, affect bead properties. Understanding these specifics is essential for proper bead handling.
  4. Efficient Bead Capture: Magnetic beads typically form a pellet attracted to the magnet within a minute. Extend the attraction time to ensure efficient bead capture.
  5. Gentle Supernatant Removal: When removing the wash solution or supernatant, angle the pipette tip to avoid disturbing the magnetic bead pellet. Ensure that the tip doesn’t come into contact with the pellet.

By following these tips, you can make the most of magnetic bead-based protein purification, improving the efficiency and reliability of your experiments.

New Publication: Cell Cited LifeTein Biotinylated Peptide Products

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Pull-down assay using biotinylated peptides

Giantin, a novel conserved Golgi membrane protein, is a disulfide-linked homodimer. It was found that BFA-induced Golgi disorganization is associated with the monomerization of giantin.

The pull-down experiment was performed. The control peptide biotin-GHGTGSTGSGSMLRTLLRRRL synthesized by LifeTein was incubated with lysate and Dynabeads, as well as the lysate incubated with Dynabeads only served as a control. Dynabeads carrying MGAT1 peptide were able to pull-down giantin from the lysate of HeLa cells, however, giantin was not detected in the pull-down fraction from the lysate exposed to the Dynabeads or in combination with control peptide. It is logical to hypothesize that the MGAT1 binding domain of giantin lies within its N-terminal non-coiled-coil area.

The Dynabeads function similarly to LifeTein magnetic beads:
https://www.lifetein.com/peptide-product/amineactivated-peptide-conjugation-magnetic-beads-p-3647.html

Cells 2019, 8(12), 1631; https://doi.org/10.3390/cells8121631

Full list of Cell-Penetrating Peptides

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Table 1 Selection of cell-penetrating peptides

(Reference: https://doi.org/10.1007/978-981-13-8747-0, Ülo Langel, CPP, Cell-Penetrating Peptides, 2019)

Name Sequence
2 DSLKSYWYLQKFSWR (Kondo et al. 2012)
18A DWLKAFYDKVAEKLKEAF (Datta et al. 2000)
α1H KSKTEYYNAWAVWERNAP (Gomarasca et al. 2017)
α2H GNGEQREMAVSRLRDCLDRQA (Gomarasca et al. 2017)
A22p HTPGNSNKWKHLQENKKGRPRR (Shin et al. 2014)
Ac-18A-NH2 DWLKAFYDKVAEKLKEAF) (Wimley and White 2000)
aCPP Typical sequence R9GPLGLAGE8 (Li et al 2015)
AdVpVI(33-55) Ac-GAFSWGSLWSGIKNFGSTVKNYG (Murayama et al. 2016)
AIP6 RLRWR (Wang et al. 2011)
all-d DsC18 Glrkrlrkfrnkikek (Bergmann et al. 2017)
αgliadin(31-43) LGQQQPFPPQQPY (Paolella et al. 2018)
Alyteserin-2a ILGKLLSTAAGLLSNL (Conlon et al. 2013)
ANG TFFYGGSRGKRNNFKTEEY (Demeule et al. 2008)
ApoE(141–150) Ac-LRKLRKRLLRX-Bpg-G (Shabanpoor et al. 2017)
ApoE-derived Ac-LRKLRKRLLR (Tailhades et al. 2017)
Arf(1-22) MVRRFLVTLRIRRACGPPRVRV (Johansson et al. 2008)
AT1002 FCIGRL (Gopalakrishnan et al. 2009)
AT1AR(304-318) FLGKKFKKYFLQLLK (Östlund et al. 2005)
Bac7 RRIRPRPPRLPRPRPRPLPFPRPGPRPIPRPL (Sadler et al. 2002)
BGPC7-FHV RRRRNRTRRNRRRVR-RRFYGPV (Wongso et al. 2017)
Bim EIWIAQELRRIGDEFNAYYARLLC (Kim et al. 2017)
BP16 KKLFKKILKKL (Soler et al. 2014)
BP100 KKLFKKILKYL (Eggenberger et al. 2009)
BPP13a GGWPRPGPEIPP (Sciani et al. 2017)
bPrPp(1-30) MVKSKIGSWILVLFVAMWSDVGLCKKRPKP (Magzoub et al. 2006)
BR2 RAGLQFPVGRLLRRLLR (Lim et al. 2013)
Buforin II TRSSRAGLQFPVGRVIIRLLRK (Park et al.1998)
Buforin IIb RAGLQFPVG[RLLR]3 (Lee et al. 2008)
C6M1 RLWRLLWRLWRRLWRLLR (Jafari et al. 2014)
C105Y CSIPPEVKFNKPFVYLI (Rhee and Davis 2006)
CADY GLWRALWRLLRSLWRLLWRA cycteamide (Crombez et al. 2009a)
CAR CARSKNKDC (Toba et al. 2014)
CA-Tat KWKLFKKYGRKKRRQRRR (Lv et al. 2017)
CB5005 M KLKLALALALA (Zhang et al. 2016)
CDB3 REDEDEIEW (Issaeva et al. 2003)
CendR RPARPAR (Hu et al. 2014)
cF<tR4 cyclic F<tRRRRQ (Qian et al. 2014)
CGKRK CGKRK (Griffin et al. 2017)
CIGB-300 cyclic CWMSPRHLGTC-Tat (Perera et al. 2012)
CIGB-552 Ac-HARIKpTFRRlKWKYKGKFW (Fernandez Masso et al. 2013)
CLIP6 KVRVRVRVpPTRVRERVK (Soudah et al. 2017)
CooP ACGLSGLGVA (Hyvonen et al. 2014)
CpMTP ARLLWLLRGLTLGTAPRRA (Jain and Chugh 2016)
CPNT STSGTGKMTRAQRRAAARRNRA (Qi et al. 2011)
CPP1 (KFF)3K (Patel et al. 2017)
CPP33 RLWMRWYSPRTRAYG (Lin et al. 2018)
CPP-C PIEVCMYREP (Nakayama et al. 2011)
CPPecp NYRWRCKNQN (Fu et al. 2017)
C-peptide GPGLWERQAREHSERKKRRRESECKAA (Fan et al. 2016)
CRGDK CRGDK (Zhao et al. 2018)
Crotamine YKQCHKKGGHCFPKEKICLPPSSDFGKMDCRWRWKCCKKGSG (Rodrigues et al. 2012)
cSN50 AAVALLPAVLLALLAPVQRKRQKLMP (Torgerson et al. 1998)
65-2CTS CPYVNQRPQKARYRNG (Percipalle et al. 2003)
CWR8K CWR8K (Sasaki et al. 2008)
CyLoP-1 CRWRWKCCKK (Ponnappan et al. 2017)
Cyt c(77–101) GTKMIFVGIKKKEERADLIKKA (Howl and Jones 2015)
DAG cyclic CDAGRKQKC (Mann et al. 2017)
D-JNKI-1 RPKRPTTLNLFPQVPRSQDT (Bonny et al. 2001)
DK17 DRQIKIWFQNRRMKWKK (Bera et al. 2016)
DLP ACKTGSHNQCG (Kumar et al. 2015)
DMBT1-derived GRVEVLYRGSW and GRVRVLYRGSW (Tuttolomondo et al. 2017)
dNP2 KIKKVKKKGRK-KIKKVKKKGRK (Lim et al. 2015)
DPV3 RKKRRRESRKKRRRES (Tacken et al. 2008)
DPV1047 CVKRGLKLRHVRPRVTRMDV (De Coupade et al. 2005)
DRTTLTN DRTTLTN (Gennari et al. 2016)
DS4.3 RIMRILRILKLAR (Jeong et al. 2014)
Dynorphin A YGGFLRRIRPKLKWDNQ (Marinova et al. 2005)
EA GLKKLAELAHKLLKLGC (Yang et al. 2014)
EB1 LIRLWSHLIHIWFQNRRLKWKKK (Lundberg et al. 2007)
EF GLKKLAELFHKLLKLGC (Yang et al. 2014)
EHB RCSHYTGIRCSHMAATTAGIYTGIRCQHVVL-C6H (Cao et al. 2018)
EPRNEEK EPRNEEK (Orihuela et al. 2009)
F3** diphosphorylated dipeptide (Miao et al. 2016)
G4R9L4 G4R9L4 (Ramakrishna et al. 2014)
GALA WEAALAEALAEALAEHLAEALAEALEALAA (Li et al. 2004)
GeT KIAKLKAKIQKLKQKIAKLK (Rakowska et al. 2014)
gH625 HGLASTLTRWAHYNALIRAF (Galdiero et al. 2015)
Gi3α(346-355) KNNLKECGLY (Jones et al. 2005)
Glu-Lys EEEAAKKK (Lewis et al. 2010)
GV1001 EARPALLTSRLRFIPK (Kim et al. 2016a)
GWH1 GYNYAKKLANLAKKFANALW (Serna et al. 2017)
H2A derived SGRGKQGGKARAKAKTRSSRAGLQFPVGRVHRLLRKG (Rosenbluh et al. 2004)
H6R6 H6R6 (Sun et al. 2017)
H16 H16 (Iwasaki et al. 2015)
HA2(1-23) GLFGAIAGFIENGWEGMIDGWYG (Esbjörner et al. 2007)
HAIYPRH HAIYPRH (Shteinfer-Kuzmine et al. 2017)
hBD3-3 GKCSTRGRKCCRRKK (Lee et al. 2015b)
HBP GKRKKKGKGLGKKRDPCLRKYK (Luo et al. 2016)
hLF KCFQWQRNMRKVRGPPVSCIKR (Duchardt et al. 2009)
Hph-1 YARVRRRGPRR (Jung et al. 2011)
HR9 CH5-R9-H5C (Liu et al. 2013a)
Hst5 DSHAKRHHGYKRKFHEKHHSHRGY (Luque-Ortega et al. 2008)
I1WL5W WKKIWSKIKKLLK (Bi et al. 2014)
I4WL5W IKKWWSKIKKLLK (Bi et al. 2014)
ID No.2 MAAWMRSLFSPLKKLWIRMH (Eudes and Macmillan 2014)
IMT-P8 RRWRRWNRFNRRRCR (Gautam et al. 2016)
INF GLFEAIEGFIENGWEGMIDGWYGC (Pichon et al. 1997)
iNGR CRNGRGPDC (Alberici et al. 2013)
isl-1 RVIRVWFQNKRCKDKK (Kilk et al. 2001)
JB9 cskc (Basu and Wickstrom, 1997)
JB434 R9GGLAA-Aib-SGWKH6 (Sangtani et al. 2018)
KAFAK KAFAKLAARLYRKALARQLGVAA (Bartlett et al. 2013)
KALA WEAKLAKALAKALAKHLAKALAKALKACEA (Wyman et al. 1997)
Kalata B1 polycyclic CGETCVGGTCNTPGCTCSWPVCTRNGLPV (Daly et al. 1999)
(KFF)3K (KFF)3K (Rownicki et al. 2017)
K-FGF AAVLLPVLLAAP (Lin et al. 1995)
KH (KH)9 (Chuah et al. 2016)
KLA KLAKLAKKLAKLAK (Huang et al. 2017)
KLAK KLALKLALKALKAALKLA (Oehlke et al. 1998)
KLA-R7 KLAKLAKKLAKLAKGGRRRRRRR (Lemeshko, 2013)
KP MAPTKRKGSCPGAAPNKKP (Villa-Cedillo et al. 2017)
KST peptide STGKANKITITNDKGRLSK (Adachi et al. 2017)
L1−6 PLILLRLLR (Schmidt et al. 2017)
L5a RRWQW (Liu et al. 2016a)
L17E IWLTALKFLGKHAAKHEAKQQLSKL (Akishiba et al. 2017)
lactoferrampin(265- 284) DLIWKLLSKAQEKFGKNKSR (Reyes-Cortes et al. 2017)
lactoferricin(17-30) FKCRRWQWRMKKLG (Reyes-Cortes et al. 2017)
lactoferrin(19-40) KCFMWQEMLNKAGVPKLRCARK (Duchardt et al. 2009)
LAH1 KKLALALALALHALALALALKKA (Moulay et al. 2017)
LALF(31-52) HYRIKPTFRRLKWKYKGKFW (Yanez et al. 2017)
LB FKCRRWQWRMKKLGAPSITCVRRAF) (Liu et al. 2013b)
L-CPP LAGRRRRRRRRRK (Liu et al. 2006)
LDP-NLS KWRRKLKKLRPKKKRKV (Ponnappan and Chugh, 2017)
LE10 LELELELELELELELELELE (Antunes et al. 2013)
LF chimera FKCRRWQWRMKKLG-K-RSKNKGFKEQAKSLLKWILD (Reyes-Cortes et al. 2017)
linTT1 AKRGARSTA (Hunt et al. 2017)
LK LKKLLKLLKKLLKLAG (Kim et al. 2016b)
LL37 LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES (Kim et al. 2016b)
LLIIL LLIIL (Alaybeyoglu et al. 2017)
LMWP VSRRRRRRGGRRRR (Chen et al. 2017d)
LP-12 HIITDPNMAEYL (Kumar et al. 2015)
LPAs RCnRCnK (Gupta et al. 2011)
LTV LTVSPWY (Chopra 2012)
lycosin-I RKGWFKAMKSIAKFIAKEKLKEHL (Tan et al. 2017)
Lyp1 CGNKRTRGC (Fogal et al. 2008)
M918 MVTVLFRRLRIRRACGPPRVRV (El-Andaloussi et al. 2007)
Maurocalcine GDCLPHLKLCKENKGCCSKKCKRRGTNIEKRCR (Poillot et al. 2010)
MAP KLALKLALKALKAALKLA (Oehlke et al. 1998)
MAP12 LKTLTETLKELTKTLTEL (Oehlke et al. 2002)
MCoTI-I polycyclic SGSDGGVCPKILQRCRRDSDCPGACICRGNGYCG (Camarero, 2017)
MCoTI-II polycyclic CPKILKKCRRDSDCPGACICRGNGYCGSGSDGGV (Huang et al. 2015)
MFK MFKLRAKIKVRLRAKIKL (Samuels et al. 2017)
Mgpe9 CRRLRHLRHHYRRRWHRFRC (Vij et al. 2016a)
MitP INLKKLAKL(Aib)KKIL (Howl et al. 2018)
m(KLA)-iRGD klaklakklakla-K-GG-iRGD (Qifan et al. 2016)
MMGP1 MLWSASMRIFASAFSTRGLGTRMLMYCSLPSRCWRK (Pushpanathan et al. 2013)
MPER fragment ELDKWASLWNWFDITNWLWYIK (Song et al. 2009)
MPG GALFLGFLGAAGSTMGA cysteamide (Morris et al. 1997)
MPG GALFLGFLGAAGSTMGASQPKKKRKV cycteamide (Deshayes et al. 2005)
MPG-8 AFLGWLGAWGTMGWSPKKKRK (Crombez et al. 2009b)
mRVG YTIWMPENPRPGTPCDIFTKSRGKRASNGGGRRRRRRRRR (Villa-Cedillo et al. 2017)
MT23 LPKQKRRQRRRM (Zhou et al. 2017)
mtCPP1 r-Dmt-OF (Cerrato et al. 2015)
MTM AAVALLPAVLLALLAP (Fletcher et al. 2010)
MTD84 AVALVAVVAVA (Lim et al. 2014)
MTP MLSLRQSIRFFK (Chuah et al. 2015a, b)
MTS KGEGAAVLLPVLLAAPG (Zhao et al. 2001)
MTS1 AAVLLPVLLAAP (Rojas et al. 1998)
Mut3DPT-C9h VKKKKIKAEIKIYVETLDDIFEQWAHSEDL (de la Torre et al. 2017)
Myr-ApoE Myr-LRKLRKRLLR (Tajik-Ahmadabad et al. 2017)
New modalities Polycyclic, hairpin, stapled peptides for delivery (Valeur et al. 2017, Waldmann et al. 2017)
NF1 Stearyl-AGY(PO3)LLGKTNLKALAALAKKIL (Arukuusk et al. 2013)
NF51 δ-(Stearyl-AGYLLG)OINLKALAALAKKIL (Arukuusk et al. 2013)
NF55 δ-(Stearyl-AGYLLG)OINLKALAALAKAIL (Freimann et al. 2016)
NLS PKKKRKV (Yoneda et al. 1992).
NLS-StAx-h stapled RRWPRXILDXHVRRVWR (Dietrich et al. 2017)
NoLS KKRTLRKNDRKKRC (Yao et al. 2015)
Novicidin KNLRRIIRKGIHIIKKYF (Milosavljevic et al. 2016)
NPFSD VLTNENPFSDP (Gong et al. 2016)
NYAD-1 stapled ITFEDLLDYYGP (Zhang et al. 2008)
Oct4-PTD DVVRVWFCNRRQKGKR (Adachi et al. 2017)
P007 Ac-(RAhxR)4-Ahx-βAla (Greer et al. 2014)
P1 LRRWSLG (Peng et al. 2017b)
P2 WKRTLRRL (Peng et al. 2017b)
P3 YGRKKRRQR (Tan et al. 2006)
P7 RRMKWKK (Watson et al. 2017)
P11 YGRKKRRQRRR (Zhao et al. 2011)
P11 HSDVHK (Bang et al. 2011)
P11LRR P11LRR (Li et al. 2010)
P14LRR (PLPRPR)4 (Brezden et al. 2016)
p18 LSTAADMQGVVTDGMASG (Taylor et al. 2009)
P21 KRKKKGKGLGKKRDPCLRKYK (Dixon et al. 2016)
P28 LSTAADMQGVVTDGMASGLDKDYLKPDD, Leu50-Asp77 of azurin (Yamada et al. 2016)
p28 FLHSGTAVTCTYPALTPQWEGSDCTHRL (Signorelli et al. 2017)
p53 peptide MO6 Stapled TSF*EYWYLL* (Chee et al. 2014)
PAF26 Ac-rkkwfw (Lopez-Garcia et al. 2002)
PAS GKPILFF (Woldetsadik et al. 2017)
pCLIP6 KVRVRVRVpP(pT)RVRERVK (Chen et al. 2017b)
pD-SP5 riPRPSPKMGV(pS)VS (Chen et al. 2017b)
PenetraMax KWFKIQMQIRRWKNKR, L- and D- (Khafagy el et al. 2015)
Penetratin RQIKIWFQNRRMKWKK (Derossi et al. 1994)
Pep-1 KETWWETWWTEWSQPKKKRKV cysteamide (Morris et al. 1997)
pepM KLFMALVAFLRFLTIPPTAGILKRWGTI (Freire et al. 2014)
pepR LKRWGTIKKSKAINVLRGFRKEIGRMLNILNRRRR (Freire et al. 2014)
Pept1 PLILLRLLRGQF (Marks et al. 2011)
Peptide 599 GLFEAIEGFIENGWEGMIDGWYGGGGRRRRRRRRRK (Alexander-Bryant et al. 2015)
Pep42 Cyclic CTVALPGGYVRVC (Kim et al. 2006)
PepNeg SGTQEEY (Neves-Coelho et al. 2017)
PepFect6 Stearyl-AGYLLGK(εTMQ)INLKALAALAKKIL, PF6 (El-Andaloussi et al. 2011)
PepFect14 Stearyl- AGYLLGKLLOOLAAAALOOLL (Ezzat et al. 2011)
PG1 RGGRLCYCRRRFCVCVGR (Liu et al. 2013b)
pHLIP AEQNPIY-WARYADWLFTTPLLLLDLALLV-DADEGT (Andreev et al. 2010)
PHPs H6-H10 peptides (Kimura et al. 2017)
PIP1 RXRRXRRXRIKILFQNRRMKWKK (Ivanova et al. 2008)
Pip5e RXRRBRRXRILFQYRXRBRXRB (Betts et al. 2012)
Pip6a Ac-RXRRBRRXRYQFLIRXRBRXRB (Lehto et al. 2014)
POD CGGG(ARKKAAKA)4 (Dasari et al. 2017)
PR9 FFLIPKG-R9 (Liu et al. 2013a)
PTD YARVRRRGPRRR (Dong et al. 2016)
PTD3 R9-ETWWETWWTEW (Kizaka-Kondoh et al. 2009)
PTD4 YARAAARQARA (McCusker et al. 2007)
Poly-Arg Most popular R7 – R12 (Mitchell et al. 2000, Futaki, 2006)
pVEC LLIILRRRIRKQAHAHSK (Elmquist et al. 2001)
Pyrrhocoricin VDKGSYLPRPTPPRPIYNRN (Otvos et al. 2000)
R4K1 Stapled Ac-RRRRKS*LHRS*LQDS (Speltz et al. 2018)
R6dGR R6dGR (Wang et al. 2017)
R8 R8 (Wender et al. 2001)
R8-dGR R8dGR (Liu et al. 2016b)
R9-H4A2 Ac-YR9-HAHAHH (Okitsu et al. 2017)
R6W3 R6W3 (Bechara et al. 2013)
R10W6 R10W6 (Bechara et al. 2013)
RA9 RRAARRARR (Alhakamy et al. 2013)
RALA WEARLARALARALARHLARALARALRACEA (McCarthy et al. 2014)
RDP CKSVRTWNEI IPSKGCLRVG GRCHPHVNGG GRRRRRRRRC (Xiao et al. 2017)
REDV REDV (Yang et al. 2016)
RF GLKKLARLFHKLLKLGC (Yang et al. 2014)
cRGDfC Cyclic RGDfC (Wada et al. 2017)
iRGD Cyclic CRGDKGPDC (Peng and Kopecek, 2015)
RGE RGERPPR (Yu et al. 2017)
RH9 RRHHRRHRR (Alhakamy et al. 2013)
RL9 RRLLRRLRR (Alhakamy et al. 2013)
RL16 RRLRRLLRRLLRRLRR (Joanne et al. 2009)
RT53 RQIKIWFQNRRMKWKKAKLNAEKLKDFKIRLQYFARGLQV YIRQLRLALQGKT (Jagot-Lacoussiere et al. 2016)
RTP004 RKKRRQRRRG-K15-GRKKRRQRRR) (Lee et al. 2015a)
RV24 RRRRRRRRRGPGVTWTPQAWFQWV (Lo and Wang, 2012)
RVG YTIWMPENPRPGTPCDIFTNSRGKRASNG (Kumar et al. 2007)
RVG-9R YTIWMPENPRPGTPCDIFTNSRGKRASNGGGGRRRRRRRRR (Rassu et al. 2017)
RVG29 YTIWMPENPRPGTPCDIFTNSRGKRASNGGGGRRRRRRRRR (Villa-Cedillo et al. 2017)
RW9 RRWWRRWRR (Alhakamy et al. 2013)
RW16 RRWRRWWRRWWRRWRR (Jobin et al. 2013)
(RXR)4 (R-Ahx-R)4 (Saleh et al. 2010)
(rXr)4 (r-Ahx-r)4 (Vij et al. 2016b)
S155 VKKKKIKREI-KIAAQRYGRELRRMADEFHV (Haidar et al. 2017)
S4(13)-PV ALWKTLLKKVLKAPKKKRKV (Mano et al. 2007)
SAP VRLPPPVRLPPPVRLPPP (Pujals et al. 2006)
SAP(E) VELPPPVELPPPVELPPP (Martin et al. 2011)
all-D-SAP (vrlppp)3 (Pujals et al. 2007)
SAPSp-lipo stearyl-GGGGHGAHEHAGHEHAAGEHHAHE (Suzuki et al. 2017)
SAR6EW SAR6EW (Im et al. 2017)
sC18 GLRKRLRKFRNKIKEK (Oren et al. 1999)
(sC18)2 (GLRKRLRKFRNKIKEK)2 (Gronewold et al. 2017)
SMTP motif, LRLLR (Fuselier and Wimley, 2017)
SPACE Cyclic ACTGSTQHQCG (Hsu and Mitragotri, 2011)
SRCRP2-11 GRVEVLYRGSW (Tuttolomondo et al. 2017)
STR-KV H3K3V6 (Pan et al. 2016)
SS-02 Dmt-r-FK (Alta et al. 2017)
SS-20 F-r-FK (Alta et al. 2017)
SS-31 r-Dmt-KF (Zhao et al. 2005)
SynB1 RGGRLSYSRRRFSTSTGR (Rousselle et al. 2000)
T2 LVGVFH (Kumar et al. 2012)
Tat(49-57) RKKRRQRRR (Vives et al. 1997a)
Tat(48-60) GRKKRRQRRRPPQ (Vives et al. 1997b)
Tat(44-57) CGISYGRKKRRQRRR (Niesner et al. 2002)
Tat(37-72) CFITKALGISYGRKKRRQRRRPPQGSQT-HQVSLSKQ (Fawell et al. 1994)
Tat analog GRKKRRQR (Nguyen et al. 2008)
Tat-LK15 Tat-KLLKLLLKLLLKLLK (Peng et al. 2017a)
TCTP MIIFRALISHKK (Bae et al. 2016)
TD-1 ACSSSPSKHCG (Chen et al. 2006)
TD2.2 SYWYRIVLSRTGRNGRLRVGRERPVLGESP (Heffernan et al. 2012)
TH peptide GYLLGHINLHHLAHL-Aib-HHIL (Chen et al. 2017a)
TM2 PKKGSKKAVTKAQKKDGA (Kochurani et al. 2015)
Transportan GWTLNSAGYLLGKINLKALAALAKKIL, TP (Pooga et al. 1998)
TP10 AGYLLGKINLKALAALAKKIL (Soomets et al. 2000)
TPk VRRFkWWWkFLRR (Bahnsen et al. 2015)
Tpl KWCFRVCYRGICYRRCRGK (Jain et al. 2015)
TPP TKDNNLLGRFELSG (Gehrmann et al. 2014)
TT1 CKRGARSTA (Paasonen et al. 2016)
vAMP 059 INWKKWWQVFYTVV (Dias et al. 2017)
vCPP 0769 RRLTLRQLLGLGSRRRRRSR (Dias et al. 2017)
vCPP 2319 WRRRYRRWRRRRRWRRRPRR (Dias et al. 2017)
VDAC(1-26) MAVPPTYADLGKSARDVFTKGYGFGL (Smilansky et al. 2015)
VP22 NAATATRGRSAASRPTQRPRAPARSASRPRRPVQ (Elliott and O’Hare, 1997)
V peptide TVDNPASTTNKDKLFAVRK (Manosroi et al. 2014)
VT5 DPKGDPKGVTVTVTVTVTGKGDPKPD (Oehlke et al. 1997)
W(RW)4 W(RW)4 (Nasrolahi Shirazi et al. 2013)
Xentry LCLR (Montrose et al. 2014)
X-pep MAARLC (Adachi et al. 2017)
YKA YKALRISRKLAK (Desai et al. 2014)
YTA2 YTAIAWVKAFIRKLRK (Lindgren et al. 2006)
YTA4 IAWVKAFIRKLRKGPLG (Lindgren et al. 2006)
Z2 FWIGGFIKKLKRSKLA (Chen et al. 2017c)
Z3 FKIKKFIGGLWRSKLA (Chen et al. 2017c)
Z12 KRYKNRVASRKCRAKFKQLLQHYREVAAAKSSENDRLRLLLK (Derouazi et al. 2015)
ZXR-1 FKIGGFIKKLWRSKLA (Chen et al. 2017c)
[/showhide]

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LifeTein Peptide Synthesis Service

LifeTein provides the fastest turnaround time and most reliable quality in the industry. Peptides are made in New Jersey, USA. Projects move from conception to bench in only 3–5 days so you can deal with your research deadlines.

Introducing LifeTein‘s faster microwave peptide synthesis technology!
LifeTein’s new platform is designed for maximized speed and efficiency. Unparalleled peptide quality, greater flexibility, and improved reliability make LifeTein the vendor of choice for all your peptide synthesis needs.

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How to form the fibrillary structure using beta-amyloid peptides or amylin?

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Aβ-(1–42) was dissolved to 1 mM in 100% hexafluoroisopropanol, hexafluoroisopropanol was removed under vacuum, and the peptide was stored at −20 °C. For the aggregation protocols, the peptide was first resuspended in dry Me2SO (DMSO) to 5 mM. For oligomeric conditions, F-12 (without phenol red) culture media was added to bring the peptide to a final concentration of 100 μM, and the peptide was incubated at 4 °C for 24 h. For fibrillar conditions, 10 mM HCl was added to bring the peptide to a final concentration of 100 μM, and the peptide was incubated for 24 h at 37 °C.

ADDLS, amyloid-derived diffusible ligands.

Preparing human islet amyloid polypeptide (hIAPP), also known as amylin, can be challenging due to its hydrophobic amino acid residues.

Here’s an improved method for dissolving lyophilized hIAPP:

  1. Begin by dissolving lyophilized hIAPP in 80% (v/v) HFIP containing 10 mM HCl. This step ensures complete dissolution. The CD spectrum indicates the presence of a stable alpha-helical conformation, which remains so for several days.
  2. Next, remove the HFIP by lyophilization, leaving behind lyophilized hIAPP.
  3. Re-dissolve the lyophilized hIAPP in 10 mM HCl, and eliminate any insoluble components by ultracentrifugation.
  4. The resulting hIAPP solution in 10 mM HCl is ready for immediate use in experiments.

To initiate the formation of hIAPP fibrils, introduce the stock solution into the reaction buffer. Conditions for fibril formation were optimized under two pH conditions:

  • Low pH: Utilize 25 uM hIAPP in 10 mM HCl, with varying concentrations of HFIP.
  • Neutral pH: Employ 25 uM hIAPP in a 50 mM sodium phosphate buffer at pH 7.0, with varying concentrations of HFIP.

Incubate these samples at 25 °C for several hours.

Reference: JOURNAL OF BIOLOGICAL CHEMISTRY 23965, JULY 8, 2011 VOLUME 286 NUMBER 27

Aducanumab is a human monoclonal antibody that has been studied for the treatment of Alzheimer’s disease.

The Nobel Prize in Physiology or Medicine 2019 was awarded jointly to William G. Kaelin Jr, Sir Peter J. Ratcliffe and Gregg L. Semenza

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Nobel Prize
HIF1a peptide Nobel Prize

LifeTein Synthesized a Key Peptide That Played a Role in the Nobel Prize in Physiology or Medicine 2019

The Nobel Prize in Physiology or Medicine 2019 was awarded jointly to William G. Kaelin Jr, Sir Peter J. Ratcliffe and Gregg L. Semenza. One of the key peptides was made by LifeTein: HIF1a-P564: DLDLEMLAPYIPMDDDFQLR.

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Formation of Azides From Primary Amines

A click chemistry was reported about the formation of azides from primary amines

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Click chemistry for drug screening

A click chemistry was reported about the formation of azides from primary amines. This powerful tool enables the reaction of just one equivalent of a simple diazotizing species, and fluorosulfuryl azide (FSO2N3), for the preparation of over 1,200 azides on 96-well plates in a safe and practical manner. This method greatly expands the number of accessible azides and 1,2,3-triazoles because the primary amine is one of the most abundant functional groups in small compounds, proteins and antibodies.

Formation of Azides From Primary Amines

The method opens the door for numerous applications in drug screening and discovery. The cell penetration peptides can be easily introduced to conjugate with any azide containing drugs, compounds, antibodies, or proteins.

The cell penetration peptides (CPPs) are capable of delivering biologically active cargo to the cell interior. The desired therapeutic cargo could be attached to a CPP using the copper free click chemistry and then delivered to an intracellular target, thereby overcoming the entry restrictions set by the plasma membrane.

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LifeTein Synthesized a Key Peptide That Played a Role in the Nobel Prize in Physiology or Medicine 2019

Braftide, a 10mer peptide synthesized at LifeTein, a potent allosteric inhibitor of BRAF dimer for cancer therapy

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Dabrafenib


BRAF is an RAF kinase. It is a core component of the RAS/RAF/MEK/ERK signaling cascade, known as mitogen-activated protein kinase (MAPK) pathway. It is one of the major effectors of oncogene RAS, and is often mutated in human cancer cells.

LifeTein’s Braftide & Cancer Therapy


Two FDA approved drugs, Dabrafenib, and vemurafenib, effectively inhibit the most common BRAF variant V600E, a monomeric BRAF. But, the non-V600E BRAF mutations are intrinsically resistant to these drugs. These drugs may also paradoxically stimulate the pathway when the tumor cells contain wild-type BRAF and oncogenic RAS, causing secondary malignancies.
The researchers tried to tackle the dimeric BRAF. The dimeric BRAF, such as the wild type and G469A, a most prevalent non-V600E variant in lung cancer cells, hinges on dimer interface (DIF), a 20aa span near the tail end of the alpha-C helix of BRAF. The researchers designed Braftide using computational modeling, aiming to block the dimerization. They tested the functionality in vitro, in HEK263 cells and colon cancer cell lines.

LifeTein synthesized Braftide (TRHVNILLFM), Null-Braftide (THHVNILLFM), Cy3-Braftide (TRHVNILLFM-Cy3), TAT-Braftide (GRKKRRQRRRPQ-PEG-TRHVNILLFM), and TAT (GRKKRRQRRRPQ). We reviewed here some of the assays that helped support Braftide as an allosteric inhibitor of BRAF dimer and down-regulator of MAPK signaling pathway for cancer therapy.


1) Cell-free in vitro assay: dose-response curve. First of all, the researchers show that Braftide has a sub-micromolar IC50 for dimeric BRAF. Full-length dimeric BRAF-WT and BRAF-G469A (from HEK293F cells) were used for dose-response curves, and the BRAF activity was probed by pMEK production.


2) Cell-free in vitro assay: Saturation binding assay. The researchers used Cy3-labeled Braftide (Cy3-Braftide) to characterize (KD) the binding of Braftide with dimeric BRAF-WT using fluorescence quantification.


3) Cell-free in vitro assay: Immunoprecipitation (IP). The purpose of IP was to show Braftide disrupted the BRAF dimerization. Braftide was added to HEK293 cell lysate coexpressing V5- and FLAG-tagged BRAF-WT. FLAG-tagged BRAF was pulled down by FLAG antibody-conjugated resin, which was further probed for V5-tagged BRAF. Braftide indeed reduced homodimer BRAF.


4) Delivery of Braftide into HEK cell for BRAF inhibition. Braftide was tagged with cell-penetrating peptide TAT. TAT-Braftide (and its negative control TAT alone) was used to treat HEK293 cells transiently transfected with BRAF-WT and BRAF-G469A. Four hours of treatment resulted in reductions of BRAF, pMEK, MEK (i.e. the MAPK pathway), which were analyzed with respective antibodies by immunoblotting.


5) Delivery of Braftide into cancer cells for BRAF inhibition and cell proliferation inhibition. Two colon cancer cell lines (KRAS-G13D-colon carcinoma) were treated with cell-penetrating TAT-Braftide and assayed for the inhibition of BRAF activity, down-regulation of MAPK signaling, and cell proliferation. All were shown positive, while the negative control TAT alone were negative.

https://pubs.acs.org/doi/abs/10.1021/acschembio.9b00191

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Synthetic Scorpion Toxin Peptides: A New Frontier in Chronic Pain Management by LifeTein

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Synthetic Scorpion Toxin Peptides
Synthetic Wasabi Receptor Toxin

Researchers at the University of California, San Francisco (UCSF), in collaboration with LifeTein, have made a groundbreaking discovery in the field of pain management. LifeTein’s expertise in peptide synthesis was crucial in developing synthetic scorpion toxin peptides that specifically target the “wasabi receptor,” a key player in the body’s response to certain types of pain.

The wasabi receptor, scientifically known as TRPA1, is an ion channel protein that triggers the familiar sinus-clearing or eye-watering sensation experienced when consuming wasabi or cutting onions. This receptor is also implicated in the perception of chronic pain.

The focus of this research is a peptide derived from scorpion toxin, referred to as WaTx. Remarkably, WaTx, synthesized by LifeTein, can activate the TRPA1 receptor, mimicking the pain response to irritants. Unlike other molecules, WaTx has the unique ability to penetrate cell membranes directly, bypassing the need for channel proteins. This property makes it an invaluable tool for studying chronic pain and inflammation.

In addition to its research applications, WaTx holds promise for the development of new, non-opioid pain therapies. It has been observed to induce pain and pain hypersensitivity without causing neurogenic inflammation, a common side effect of many pain treatments.

Expanding the Horizon: Spider Venom and Chronic Pain

Further expanding on this concept, a study titled “Identification and Characterization of ProTx-III [μ-TRTX-Tp1a], a New Voltage-Gated Sodium Channel Inhibitor from Venom of the Tarantula Thrixopelma pruriens” delves into the potential of spider venoms in pain management. This study, conducted by F. C. Cardoso and colleagues, discovered a novel inhibitor, μ-TRTX-Tp1a (Tp1a), from the venom of the Peruvian green-velvet tarantula. Tp1a selectively inhibits human NaV1.

7 channels, which are key contributors to pain perception.

The study found that Tp1a, both in its recombinant and synthetic forms, preferentially targets NaV1.7 channels, offering a new avenue for analgesic drug development. Unlike many other spider toxins affecting NaV channels, Tp1a does not significantly alter the voltage dependence of activation or inactivation of these channels. This unique feature of Tp1a was demonstrated to be effective in reversing spontaneous pain in animal models.

The structural analysis of Tp1a revealed an inhibitor cystine knot motif, common in spider toxins but with distinct pharmacological properties that could be crucial in developing more selective and potent treatments for chronic pain.

Conclusion

The research at UCSF, along with the findings on spider venom peptides and the significant contributions of LifeTein in peptide synthesis, represents a significant step forward in understanding and potentially treating chronic pain. These discoveries highlight the vast potential of natural toxins in medical research, offering hope for more effective and safer pain management strategies in the future.

Reference:

  • Lin King, J. V., Emrick, J. J., Kelly, M. J. S., Herzig, V., King, G. F., Medzihradszky, K. F., & Julius, D. (2019). A Cell-Penetrating Scorpion Toxin Enables Mode-Specific Modulation of TRPA1 and Pain. Cell. doi:10.1016/j.cell.2019.07.014