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
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
Analyzing cell interactions was always vital for biological studies, but a simple approach from microscopy fails to provide any information on receptors and ligands involved in these interactions. Scientists have developed a method of bacterial sortase labeling involving a fluorescent LPXTG peptide motif and Staphylococcus aureus transpeptidase Sortase A (SrtA) that can be readily detected using flow cytometry. The group coined this approach as Labeling Immune Partnerships by SorTagging Intercellular Contacts, or LIPSTIC for short. LIPSTIC is even more useful in the fact that the LPETG peptide and SrtA reaction allows analysis of cell-cell interactions both in vitro and in vivo.
LPETG peptide and SrtA reaction to label receptor and ligand interactions.
LifeTein supplied the group with the necessary Biotin-ahx-LPETG peptide, where in the LIPSTIC method a ligand or receptor of note that is fused with a tag consisting of five N-terminal glycine residues (G5) has the fluorescent peptide donated to it by the SrtA. The acceptor cell can then be monitored via the label after separation. The group is confident that LIPSTIC is an efficient method to label receptor-ligand interactions both in vitro and in vivo, even able to detect rare or low-intensity interactions.
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 labelling. Nature. 2018 Jan 25;553(7689):496-500. doi: 10.1038/nature25442. Epub 2018 Jan 17. PMID: 29342141; PMCID: PMC5853129.
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.
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 simultaneously circumventing the limitations caused by the formation of 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 to 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 the scientists and researchers because it allows them to finish their proteomics projects in a fast and cost-efficient manner.
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 tumour growth for patients with glioblastoma.
The anti-apoptotic factor Bcl-2 is over-expressed in B-cell lymphoma cells as their main survival mechanism by binding to IP3R2 on endoplasmic reticulum (ER). In this study, a cell-penetrating version of 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.
A patent has been published that describes new methods of manipulating plant stomatal development through artificially controlling how CRSP is expressing in plant cells. The cleavage of epidermal patterning factor 2 (EPF2) by a serine protease CRSP is a key regulating mechanism in plant stomatal development. A 30-mer EPF2 peptide, dual-tagged with DABCYL and EDANS, was synthesized by LifeTein to evaluate the protease activity of synthetic CRSP in a FRET assay.
MAP is a pathogenic bacterium infecting livestock and found prevalent in dairy products. Because some of its proteins are sequentially homologous to human zinc transporter 8 (ZnT8) protein and proinsulin (PI), children could develop autoimmunity against ZnT8 and PI after being exposed to MAP in dairy foods, and generating antibodies against MAP, and might subsequently develop type I diabetes. The hypothesis was tested by using ZnT8, PI and MAP peptides synthesized by LifeTein to assess the cross-reactivity of antibodies in sera samples from at-risk children.
The therapeutic monoclonal antibody cetuximab is among the latest arsenal developed for war on cancer, designed to block tumor growth by specifically targeting the extracellular domain of EGFR on the surface of cancer cells. Alarmingly, resistance to cetuximab has been observed. Using peptides containing methylated arginine residues synthesized by LifeTein to generated specific antibodies in mice, the researchers were able to pinpoint Arg198 and Arg200 of EGFR were methylated by protein arginine methyltransferase 1 (PRMT1) in colorectal cancer cells, which could be critical for cetuximab resistance. Their results paved a way for developing better treatment for cancer patients.