Tag Archives: peptide

peptide and peptide synthesis

Protease OMA1 Activity is Measured by MCA Fluorescent Peptide

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MCA Fluorescent Peptide
– Fig. 1. Basis of the OMA1 activity using fluorescence-based peptide.
Fluorescence is released when OMA1 recognizes and cleaves the OPA1 8-mer
peptide (fluorescence reporter) presumably at the RA site, from the cited paper

The continual fission and fusion the Mitochondria undergoes to change its shape and function are a key trait of the organelle, one that is regulated by the enzyme OMA1. However, there is little known regarding OMA1 due to the lack of a consistent method to measure its activity. More information is needed to truly gauge the role of OMA1 as a therapeutic agent. This is where one group sought to measure this activity utilizing a fluorescence-based reporter cleavage assay, one where the protease OMA1 activity is measured by MCA fluorescent peptide.

OMA1 activity measured by (MCA-AFRATDHG-(lys)DNP) peptide

The group arrived at this specific sequence as it includes the specific point on protein OPA1 (between the arginine and alanine) that OMA1 cleaves. They would then be able to spectrofluorometrically measure the fluorescent MCA moiety after the cleavage takes place. The assay proved successful in measuring the activity of OMA1, and in an inexpensive manner. The work clearly lays out the foundation for future studies of OMA1, in both its normal and abnormal pathology.

Julia Tobacyk, Nirmala Parajuli, Stephen Shrum, John P. Crow, Lee Ann MacMillan-Crow, The first direct activity assay for the mitochondrial protease OMA1, Mitochondrion, Volume 46, 2019, Pages 1-5, ISSN 1567-7249, https://doi.org/10.1016/j.mito.2019.03.001.

Revolutionary Antimicrobial Peptides: A New Hope in the Battle Against Citrus Greening

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Antimicrobial Peptides

Citrus greening, or Huanglongbing (HLB), is a disease that devastates citrus production all over the world. The culprit behind HLB is the bacterium Candidatus Liberibacter spp. (e.g., CLas), an unculturable pathogen that has proven very difficult to treat. Once a tree is infected, it becomes unproductive and dies within years, costing the global citrus market billions. While current attempts to combat HLB rely on controlling the insect vector, scientists have turned some attention toward the potential of peptides. Their work displayed how antimicrobial peptides show promise for combatting citrus greening, mainly by methods against CLas itself.

Antimicrobial peptides effective against CLas bacteria

With not many current effective options to fight HLB, scientists believe the next area of interest is targeting the CLas secretory pathway using antimicrobial peptides provided by LifeTein. Specifically, the antimicrobial peptides would be blocking the TolC efflux pump protein. The study found three peptides capable of doing this by binding tightly with the TolC receptors and even the β barrel entrance of the protein as well. Treatment with peptides in this manner showed effective inhibition and even mortality in models closely resembling CLas.

The studies displayed using antimicrobial peptides show major promise for future treatment of HLB. With the chemical-resistant bacteria CLas being nearly impossible to slow down, peptides just may have been holding the solution all along. There is hope that new therapies can be developed utilizing the strategies shown, and global citrus production can rest easy after decades of HLB ravaging the farms.

Wang, Haoqi, Nirmitee Mulgaonkar, Samavath Mallawarachchi, Manikandan Ramasamy, Carmen S. Padilla, Sonia Irigoyen, Gitta Coaker, Kranthi K. Mandadi, and Sandun Fernando. 2022. “Evaluation of Candidatus Liberibacter Asiaticus Efflux Pump Inhibition by Antimicrobial Peptides” Molecules 27, no. 24: 8729. https://doi.org/10.3390/molecules27248729

The Vital Role of 14-3-3γ in Influenza A Virus Replication

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14-3-3γ

Influenza A is a virus responsible for multiple pandemics over the last centuries, the respiratory disease has claimed millions of lives over the course of human history. Though other pandemics may come to mind in recent years, flu season is just starting up again now as the weather gets chillier. While we can fight back the virus on a yearly basis, more understanding is requited for a long-term victory. A team has been researching into the NS1 protein of the virus, the part responsible for downregulating the antiviral response of host cells to facilitate viral replication. They believe their work has revealed information on the vital role of 14-3-3γ in influenza A virus replication, where the isoform was found to interact with the protein.

Truncated N-Terminus interacts with 14-3-3γ

The group preformed much work such through immunoprecipitation to show the interactions between 14-3-3γ and the influenza A encoded NS1 protein. Some of their most compelling finds was the inhibition of 14-3-3γ expression in the host cells greatly reduced replication of the PR8 wild-type virus, but had no such effect on the R8-NS1/1-98 mutant virus, which lacks most of the effector domain of NS1. LifeTein was able to provide the group with anti β-tubulin antibodies, which assisted in their immunoprecipitation methods.

The team insists that the evidence points directly towards the vital role of 14-3-3γ in influenza A virus replication thanks to the NS1 protein. While they are still unclear on the precise mechanisms of these interactions, they are certain the findings have laid out the groundwork for future pivotal studies involving influenza A and the role of 14-3-3γ in infection.

Kuo, R.-L.; Tam, E.-H.; Woung, C.-H.; Hung, C.-M.; Liu, H.-P.; Liu, H.M.; Wu, C.-C. Interactome Profiling of N-Terminus-Truncated NS1 Protein of Influenza A Virus Reveals Role of 14-3-3γ in Virus Replication. Pathogens 2022, 11, 733. https://doi.org/10.3390/pathogens11070733

Peptides Fold and Self-Assemble on Graphite-Water Interfaces

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J. Chem. Inf. Model. 2022, 62, 17, 4066-4082

The concept of self-assembling peptides is a promising front where construction of devices can be achieved through a single molecule. While the outcome is enticing, the means to reach a consistent outcome are complex to say the least. Dozens of factors go into how a peptide may self-assemble and fold, with the most important being the sequence itself. While this can be handled by careful screening and simulations, the interface at which this folding occurs becomes more important to consider at well. Researchers looked to test how specific peptides fold and self-assemble on graphite-water interfaces, where a number of factors give this method the advantage over doing so in free solution.

Graphite helps peptides self fold into conformations

The group studying this phenomenon claimed that the folded conformations of the peptides were stable over a variety of temperatures when observed over graphite. They point out that it is due to the peptide backbone aligning with the zigzag directions of the graphite plane, thus allowing the conformations to occur more favorably from the intermolecular hydrogen bonds of the molecule. Atomic force microscopy revealed these theories to be true beyond initial simulations as well.

The team believes the design principles displayed in these experiments could be of great use in future iterations of self-assembling peptide engineering. The thermodynamically favored self-assembly with the use of a graphite-water interface shows promise as a medium for even more complex molecular devices in the future, a future LifeTein is looking forward to being a part of.

Justin Legleiter, Ravindra Thakkar, Astrid Velásquez-Silva, Ingrid Miranda-Carvajal, Susan Whitaker, John Tomich, and Jeffrey Comer
Journal of Chemical Information and Modeling 2022 62 (17), 4066-4082
DOI: 10.1021/acs.jcim.2c00419

Revolutionary LIPSTIC Method with LPETG Peptide Illuminates Receptor-Ligand Interactions In Vivo And In Vitro

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LPETG Peptide
-LIPTSTIC mechanism, from the cited paper.

Cell interaction analysis is a cornerstone of biological research, providing critical insights into the intricate world of molecular communication within living organisms. While traditional microscopy offers a glimpse into these interactions, it often falls short when it comes to revealing the specific receptors and ligands involved. Enter a groundbreaking method known as Labeling Immune Partnerships by SorTagging Intercellular Contacts, or LIPSTIC for short, which has been developed by a team of innovative scientists using LPETG Peptide.

At the heart of LIPSTIC lies the ingenious combination of a fluorescent LPXTG peptide motif and Staphylococcus aureus transpeptidase Sortase A (SrtA), offering a highly effective means of tracking and studying cell interactions. This novel approach is readily detectable through flow cytometry, making it a game-changer in the field of biological research.

The LIPSTIC method hinges on the LPETG peptide and SrtA reaction, a technique that allows for the labeling of receptor and ligand interactions. LifeTein, a leading supplier in the life sciences industry, played a pivotal role by providing the necessary Biotin-ahx-LPETG peptide to the research group. In the LIPSTIC method, a noteworthy ligand or receptor is fused with a tag composed of five N-terminal glycine residues (G5). The SrtA enzyme then graciously donates the fluorescent peptide to this fusion, enabling precise monitoring of the acceptor cell post-separation.

One of the most impressive aspects of LIPSTIC is its versatility. It empowers scientists to analyze cell-cell interactions both in vitro and in vivo, offering a comprehensive understanding of molecular partnerships in various biological contexts. Moreover, LIPSTIC’s sensitivity is a standout feature, as it can even detect rare or low-intensity interactions that might have otherwise remained hidden.

In conclusion, the introduction of the LIPSTIC method marks a significant advancement in the field of cell interaction analysis. Its ability to unveil the intricacies of receptor-ligand interactions in living systems, along with its applicability in diverse research settings, positions LIPSTIC as a powerful tool for scientists striving to unlock the secrets of cellular communication.


Pasqual G, Chudnovskiy A, Tas JMJ, Agudelo M, Schweitzer LD, Cui A, Hacohen N, Victora GD. Monitoring T cell-dendritic cell interactions in vivo by intercellular enzymatic labeling. Nature. 2018 Jan 25;553(7689):496-500. doi: 10.1038/nature25442. Epub 2018 Jan 17. PMID: 29342141; PMCID: PMC5853129.

αCT1 Peptide Weakens Cancerous Glioma Cells

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αCT1 Peptide

Glioblastoma (GBM) is the most commonly occurring terminal brain cancer. Due to complications in the brain like the blood brain barrier, methods of treating GBM are few and far between. Therefore, treatment in the region is generally left to specific chemotherapeutics like temozolomide (TMZ), which has the unique capability to bypass the brain blood barrier. However, matters become more complicated as many subpopulations of GBM, namely the glioma stem cell populations, are resistant to TMZ. Researchers are looking into ways to bypass this resilience, namely connexin 43 (Cx43) hemichannels that when inhibited by mimetic peptides allow the glioma stem cell populations to be treated significantly more effectively by TMZ

Cx43 mimetic peptides weaken cancer’s resistance to TMZ

Researchers used LifeTein’s peptide synthesis service to create two mimetic peptides of Cx43, αCT11 and αCT1, to inhibit Cx43 hemichannels and then sensitize the glioma cells and other GBM cell populations to TMZ in a 3D hyaluronic acid and collagen hydrogel-based tumor organoid system. After testing this model extensively, the group found that only the αCT1 peptide in combination with TMZ proved effective in treating the cell lines. It is believed that the αCT1 is more successful due to its cell penetrating sequence when compared to αCT11.

Overall, the group emphasizes that the model used does not accurately mimic the cellular heterogeneity of GBM, but the results are a fantastic start and can be used as a tool to further study treatment of this aggressive brain cancer. Further work can optimize this treatment and can hopefully provide a chance for those who have to go against this fatal ailment.

Jingru Che, Thomas J. DePalma, Hemamylammal Sivakumar, et al. αCT1 Peptide Sensitizes Glioma Cells to Temozolomide in a Glioblastoma Organoid Platform. Authorea. April 29, 2022.

Exploring the Role of Methylated Peptides in Histone Methylation: A LifeTein Perspective

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cell-penetration-peptide
cell-penetration-peptide

Histone methylation, a process that can signal either transcriptional repression or activation, is increasingly recognized for its interrelation with DNA methylation in mammals. For instance, the targeting of DNA methylation is intricately linked to H3K9 methylation, a key regulatory mechanism in gene expression. The p53 gene, known as the guardian of the genome and frequently mutated in human cancers, is regulated by various PTMs, including methylation.

Post-translational modifications (PTMs) of histone proteins, such as acetylation, methylation, and phosphorylation, are pivotal in regulating chromatin dynamics. Among these, the role of methylation, particularly at arginine or lysine residues, stands out for its complexity and significance. LifeTein, a leader in peptide synthesis, has contributed significantly to this field by synthesizing mono-, di-, or tri-methylated peptides. These peptides are instrumental in studying protein-protein interactions, especially in the context of histone methylation.

LifeTein’s contribution to this research is highlighted in a study focusing on the ASHH2 CW domain, which recognizes the methylation state at lysine 4 of histone 3 N-terminal tails. This domain is crucial in recruiting the ASHH2 methyltransferase enzyme to histones. The study utilized H3 histone tail mimicking peptides, specifically monomethylated (ARTK(me1)QTAR), dimethylated (ARTK(me2)QTAR), and trimethylated (ARTK(me3)QTAR) peptides, all synthesized by LifeTein with a remarkable 95% purity as confirmed by mass spectrometry.

The research documented the assignment of a shortened ASHH2 CW construct, CW42, which showed similar binding affinity and better expression yields than previous constructs. This advancement is significant in understanding how different methylation states affect protein-peptide interactions. The study also performed 1H–15N HSQC-monitored titrations to determine the saturation point of the protein-peptide complex. The findings revealed that the CW42 domain, when bound to the monomethylated histone tail mimic, showed similar perturbations in shifts as the di- and tri-methylated instances.

In summary, LifeTein’s synthetic methylated peptides have been instrumental in advancing our understanding of histone methylation. Their high-purity peptides have enabled researchers to delve deeper into chromatin dynamics and gene regulation complexities, paving the way for future discoveries in epigenetic therapies and cancer treatment.

Read the full article on SpringerLink](https://link.springer.com/article/10.1007/s12104-018-9811-x) for more detailed insights into this groundbreaking research.

LifeTein Launches Rush Custom Peptide Synthesis Service: Peptide Delivered in 3-5 Days

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Peptide-Library
Peptide-Library

LifeTein is unveiling an expedited peptide synthesis program, promising to place peptides in its customers’ hands within 3-5 business days. The RushPep™ peptide synthesis service was designed to circumvent the existing limitations of conventional solid-phase peptide synthesis (SPPS), which involves a long coupling time and low yield. RushPep™ shortens the time needed for individual coupling, deprotection, and washing steps. The proprietary methodology renders processing ten times faster than in classical synthesis while circumventing the limitations caused by forming by-products or intermediates to which traditional SPPS approaches are subject.

LifeTein’s Rush Custom Peptide Synthesis Service

“When designing the RushPep™ methodology, our focus was not only to produce peptides of high quality and purity but also to offer a streamlined solution that would increase the efficiency of researchers’ protein discovery workflows,” stated Dr. Ya Chen, Head of LifeTein’s Rush Peptide Synthesis Group. “RushPep™ achieves these goals by synthesizing the peptides in 3–5 business days to accelerate research and discovery.”

Chen continued, “The reliability of RushPep™ rush peptide synthesis ensures that the peptides are finished in 3–5 business days with high-batch-to-batch reproducibility. ” Most of the crude peptides have a purity of over 80%. RushPep™ peptide service is valuable for scientists and researchers because it allows them to finish their proteomics projects quickly and cost-effectively.

ID2 peptide for inhibition of tumour growth

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Biotinylated wild-type and modified (pT27 and T27W) ID2 peptides (amino acids 14–34) were synthesized by LifeTein. ID2 binds to the VHL ubiquitin ligase complex. This ID2 peptide could be used to inhibit tumor growth in patients with glioblastoma.

LifeTein’s ID2 Peptides Can Inhibit Tumour Growth

Nature, 529, 172–177 (14 January 2016) doi:10.1038/nature16475, An ID2-dependent mechanism for VHL inactivation in cancer.

How BIRD-2 Peptide Takes Down B-Cell Lymphoma?

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The anti-apoptotic factor Bcl-2 is over-expressed in B-cell lymphoma cells as their primary survival mechanism by binding to IP3R2 on the endoplasmic reticulum (ER).  In this study, a cell-penetrating version of the BIRD-2 peptide (Bcl-2/IP3R Disrupter-2 peptide with a TAT sequence) made by LifeTein was used to break up the complex formed by Bcl-2 and IP3R2 in human diffuse large B-cell lymphoma (DLBCL) cells. Ca2+ signaling-related events are suggested to be the killing mechanism of BIRD-2 peptide on DLBCL cells.

BIRD-2, a peptide that explicitly disrupts the Bcl2/IP3R complex, was utilized to further verify the mitochondrial Ca2+ regulatory mechanism via the Bmal1-Bcl2/IP3R signaling pathway. It was found that BIRD-2 aggravated mitochondrial Ca2+ overload and apoptosis in vitro.

Purchase BIRD-2 peptide now. Click here.

BIRD-2 peptide (sequence: RKKRRQRRRGGNVYTEIKCNSLLPLAAIVRV) was purchased from LifeTein (South Plainfield, NJ, USA) with a purity of >85%.

Bird-2 Peptides & B-Cell Lymphoma

Reference:

BIRD-2 peptide (LifeTein, USA), specifically disrupting the Bcl2/IP3R complex, was used in HGHP-treated H9c2 cells for 12 h (20 μM)

Inhibiting Bcl-2 via its BH4 domain in DLBCL cancers to provoke pro-apoptotic Ca2+ signaling

BIRD-2, a BH4-domain-targeting peptide of Bcl-2, provokes Bax/Bak-independent cell death in B-cell cancers through mitochondrial Ca2+-dependent mPTP opening