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Protein and Peptide Letters

Leiyu Zhang, Yanrui Ding
Hydrogen Bonds (HBs) play an important role in stabilizing the protein. Long time molecular dynamics simulation was performed at different temperatures to study the dynamics of HBs and HB networks of Wild Type Lipase (WTL) (Tm=56℃) and mutant 6B (Tm = 78.2℃). The persistence values of HBs formed by mutations A15S, A20E, G111D, M137P and N166Y are different from those of WTL, especially for mutation N166Y. The higher HB persistence value generally means that the HB is more stable. These mutations directly improve the stability of these HBs referring to their persistence values, which show that mutations strengthen the ability of HBs to withstand high temperature and then stabilize the secondary structure...
May 2, 2017: Protein and Peptide Letters
Edwin J A Veldhuizen, Maaike R Scheenstra, Johanna L M Tjeerdsma-van Bokhoven, Maarten Coorens, Viktoria A F Schneider, Floris J Bikker, Albert van Dijk, Henk P Haagsman
The Porcine Myeloid Antibacterial Peptide (PMAP)-23 is a porcine host defence peptide with described strong antibacterial activity against Gram-positive and Gram-negative bacteria, and fungi. In this study, PMAP-23 and short and/or mutated derivatives were tested for antibacterial and immunomodulatory activities to determine core elements of the peptide required for functionality. Shortening of the peptide on either N- or C-terminus did not lead to a strong reduction in antibacterial activity, but interestingly, all C-terminal truncated forms were strongly inhibited by salt addition...
April 28, 2017: Protein and Peptide Letters
Hyeongseok Yun, Sungrae Lee, Sumi Kim, Jiyeon Yu, Nari Lee, Jinhee Lee, Nam Doo Kim, Chiho Yu, Jaerang Rho
Human prolidase is a proline-specific metallopeptidase that catalyzes the hydrolysis of dipeptides containing a proline residue at the C-terminus. Human prolidase also has weak hydrolytic activity for toxic organophosphorus compounds, including diisopropyl fluorophosphate (DFP), sarin and soman. In this study, we performed in silico analysis to improve the catalytic activity of human prolidase towards DFP hydrolysis. We predicted that single amino acid substitution mutations of either A252R or P365R could form a salt bridge between the A252R mutant residue and the E249 residue or the P365R mutant residue and the E424 residue...
April 28, 2017: Protein and Peptide Letters
Man Man Zong, Chuan Jie Zhou, Yuan Nan Yu, Yang Zheng, Xiu Li Feng, Pu Yan Chen, Mei Yang
The bursa of Fabricius (BF) is the acknowledged humoral central immune organ and plays vital role on B lymphocyte development. In the study, a new tetrapeptide of GERA isolated from BF was named bursal peptide tetrapeptide (BP4). To investigate the immunomodulatory function of BP4 on antigen-specific immune responses, BALB/c mice were immunized with inactivated influence virus (AIV, H9N2 subtype) vaccine and BP4 at three experimental dosages. The results showed that BP4 enhanced the increased AIV-specific antibody and cytokine production, and modified T cell subtype population...
April 25, 2017: Protein and Peptide Letters
Xin-Guo Zhang, Wen-Na Wang, Chun-Sheng Zhang, Kun Li, Guo-Di Ma, Jian-Yong Li
Delta sleep-inducing peptide (DSIP) is a nonapeptide that could promote sleep through the induction of slow wave sleep. To further study the pharmacological effect of DSIP on insomnia, we designed a fusion protein containing N-terminal TAT-based transduction domain followed by human serum albumin and DSIP and designated this protein as PHD fusion protein. We expressed PHD fusion protein in Pichia pastoris, purified it to near homogeneity by three-step chromatography and performed bioactivity assay. The pharmacological activity of PHD fusion protein was studied using classic pentobarbital-induced sleep test in healthy mice...
April 25, 2017: Protein and Peptide Letters
Yahong Wu, Wenjie Zhai, Meng Sun, Zhe Zou, Xiuman Zhou, Guodong Li, Zhongyi Yan, Yuanming Qi, Yanfeng Gao
Cytotoxic CD8+ T lymphocytes (CTLs) play an important role in killing tumor cells. To develop therapeutic vaccines that can induce specific immune response, we designed a novel recombinant multiepitope vaccine YL66 which consists of HLA-A2-restricted CTL epitopes from two widely expressed tumor antigen cyclooxygenase-2 and MAGE-4, linked with membrane permeable Tat-PTD and the universal T helper epitope. The DNA fragment of YL66 was cloned into pGEX-4T-2-YL66 and pcDNA3.1(+)-YL66, respectively. Then, we tested whether the expressed protein GST-YL66 and DNA vaccine pcDNA3...
April 19, 2017: Protein and Peptide Letters
Gundeep Kaur, Harpreet Singh, Kirandeep Kaur, Suchismita Roy, Ashwani Pareek, Prabhjeet Singh
Oxidative conditions result in inhibition of peptidyl-prolyl cis-trans isomerase (PPIase) activity of several cyclophilins. Thiol groups have been implicated in redox regulation of these proteins. In our previous study, we proposed that activity of wheat cyclophilin, TaCYPA-1, may be modulated through a novel dual mechanism of redox regulation. To further understand the regulation of PPIase activity of TaCYPA-1, we generated mutants of TaCYPA-1 by substituting cysteine residues at positions -40 and -122 with serine, and at -126 with proline...
April 17, 2017: Protein and Peptide Letters
Yu Gao, Hong-Mei Zhang, Piwu Wang, Mei Li
Peptidyl-prolyl cis-trans isomerase (PPIase) catalyzes the conversion between the cis and trans configurations of proline which switches the backbone conformation of peptides. We have determined the crystal structure of the C-terminal domain of a PPIase from Pseudomonas syringae pv. tomato DC3000 (PSPTO DC3000) at 1.6 Å resolution. Structural comparison of PSPTO-PPIase with its homologues suggests that the successive arrangement of residues with short side chains in loop 4 contributes to its substrate specificity...
April 13, 2017: Protein and Peptide Letters
Amala Arumugam, Arnold Emerson Isacc
Depiction of protein structures as networks of interacting residues has enabled us to understand the structure and function of the protein. Previous investigations on closeness centrality have identified protein functional sites from three- dimensional structures. It is well recognized that ligand binding to a receptor protein induces a wide range of structural changes. An interesting question is, how central residues function during conformational changes triggered during ligand binding? The aim of this study is to comprehend at what extent central residues change during ligand binding to receptor proteins...
April 13, 2017: Protein and Peptide Letters
Jessica K Moisan, Fatma Meddeb-Mouelhi, David M Charbonneau, Marc Beauregard
Understanding the relationship between enzymatic stability and the amino acid sequence encoding such enzymes is of utmost importance. Here we thoroughly characterized the behavior of the carboxylesterase EstGtA2 from Geobacillus thermodenitrificans during thermal denaturation at different pH with various salt concentrations. EstGtA2 was characterized by circular dichroism regarding conformation and thermal stability, by dynamic light scattering for detection of association/aggregation, by enzymatic assays for activity, and by monitoring the impact of heat treatments on activity...
April 4, 2017: Protein and Peptide Letters
Arti Sharma, Sarkaraisamy Ponmariappam, Sarita Rani
Intestinal botulism is an infectious form of botulism in which disease results from ingesting spores, which is followed by spore germination and intraluminal production of botulinum neurotoxins over an extended period. Botulinum neurotoxin is produced by endospore forming bacteria called C. botulinum. The immunoproteomic is used to screen the cross reactive immunogenic proteins of C. botulinum type B using C. botulinum type B live spore antiserum. The whole cell proteins are separated by two dimensional gel electrophoresis and transferred to polyvinylidene difluoride membranes...
April 4, 2017: Protein and Peptide Letters
Ali Anvar, Rouhollah Vahabpour, Iman Salahshourifar, Azam Bolhassani
High mobility group box 1 (HMGB1) is a highly conserved protein present in the nuclei and cytoplasm of cells which has an important role as a mediator of inflammation in the extracellular environment. HMGB1 was identified as an innate adjuvant that induces immune responses against soluble antigens in vivo. In the current study, we used a baculovirus expression system for insect cells that was based on expression of HMGB1 with target gene (GFP), and purified the recombinant HMGB1-GFP fusion protein. We then demonstrated whether immunogenicity of GFP changes in the presence or absence of recombinant HMGB1 acting as an adjuvant in C57BL/6 and BALB/c mice...
April 4, 2017: Protein and Peptide Letters
Fang Zhang, Min Wang, Zheng Qiu, Xiao-Meng Wang, Chun-Lei Xu, Xia Zhang
Phage display has been proved in drug development as a high-throughput method for identifying specific cellular target of different drugs. However, phage display remains an intricate process for insoluble small chemicals because of the difficulty of presenting the molecules to the phages without occupying or destroying the very limited functional groups. In the present study, with Strychnine (Stry) selected as a model compound, we have developed an alternative in vitro bio-panning method against insoluble suspension...
April 4, 2017: Protein and Peptide Letters
Shima Tarahomi, Reza H Sajedi, Hossein Rahmani, Bijan Ranjbar, Majid Taghdir
Bioluminescence in Ca2+-binding photoproteins is an intramolecular reaction triggered by the addition of Ca2+. A comparative study has been done on Ca2+-depleted and Ca2+-loaded apo-mnemiopsin to understand the structural transition of the photoprotein by Ca2+ binding. Ca2+ is removed by TCA (trichloroacetic acid) precipitation to obtain Ca2+-depleted apo-mnemiopsin. UV-visible, CD and fluorescence spectroscopic studies demonstrate that the addition of Ca2+ is brought about by the overall structure of apo-mnemiopsin becomes more open in a concentration-dependent manner without significantly influencing the secondary structure and indicate that the Ca2+-depleted form of apo-mnemiopsin, in contrast to most other EF-hand calcium binding proteins, adopt a closed conformation when compared to the Ca2+-loaded form...
March 10, 2017: Protein and Peptide Letters
Guixin Qin, Rui Han, Bao Zhao, Hailong Jiang, Mohammed Hamdy Farouk, Chun Zhang, Dongsheng Che
Dietary iron is a crucial nutrient element for biological processes of both hosts and gut microbiota. Deficiency in dietary iron is a highly common disorder in the developing locations of the world and can be healed by oral iron administration or complementary iron diet. While the redundant iron that enters the gut lumen leads to negative effects, and modulates the gut microbial composition and function. Such modulation led to a significant effect on vital biological pathways of the host, including metabolic disease (obesity and type 2 diabetes), metabolites (SCFA, blood glucose and cholesterol), bile acid metabolism, endocrine, neural, and other well-being patterns...
March 5, 2017: Protein and Peptide Letters
Sarita Sarita, Ponmariappan Sarkaraisamy, Arti Sharma, D V Kamboj, A K Jain
Clostridium botulinum is an obligate anaerobic, Gram positive bacterium that secretes extremely toxic substances known as botulinum neurotoxins (BoNTs) that cause serious paralytic illness called botulism. Based upon the serological properties, these neurotoxin have been classified into seven serotypes designated from A to G. Due to extreme toxicity of BoNTs, these neurotoxins have been designated as category A biowarfare agents. There is no commercial neutralizing antibody available for the treatment of botulism...
March 1, 2017: Protein and Peptide Letters
Chang Zheng, Xiaojuan Zhang, Zhen Zhao, Xiaofei Hao, Jing Wei, Jian Sun
B-cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL) play vital roles in the pathogenesis of autoimmune diseases. B cell maturation antigen (BCMA), a receptor of both BAFF and APRIL shows higher affinity for APRIL than for BAFF. In this study, the conserved region of BCMA was divided into two segments BCMA1 (NEYFDSLLHACIPC) and BCMA2 (QLRCSSNTPPLT) with the aim to investigate their contribution to the ligands binding, BCMA1 contains the conservative DxL domain while BCMA2 is the segment outside the main functional area...
March 1, 2017: Protein and Peptide Letters
Bin Liu, Kaiqiao Jia, Yu Yang, Siyuan Hao, Caijie Lu, Fengming Xu, Dehui Feng, Runzhi Zhu
It was explored that CYP1 family of cytochromes P450 were over-expressed in several types of cancer. Our study aimed to characterize anti-proliferative activity and metabolism of the natural flavonoid diosmetin in the human hepatoma cell HepG2, expressing CYP1 family. Dios-induced cell apoptosis could be reversed due to p53 blockade and the cellular P53 and CYP1A1/CYP1A2 proteins levels were examined. P53 and CYP1A1/CYP1A2 proteins were up-regulated by Dios; when PFT-α was added into cells, the P53 levels were down-regulated accompanied with up-regulated CYP1A1/CYP1A2...
February 27, 2017: Protein and Peptide Letters
Yan Cai, Jinhyuk Lee, Wei Wang, Yong-Doo Park, Guo-Ying Qian
Cu2+ is well known to play important roles in living organisms having bifacial distinction: essential microelement that is necessary for a wide range of metabolic processes but hyper-accumulation of Cu2+ can be toxic. The physiological function of Cu2+ in ectothermic animals such as Pelodiscus sinensis (Chinese soft-shelled turtle) has not been elucidated. In this study, we elucidated effect of Cu2+ on the energy producing metabolic enzyme creatine kinase (CK), which might directly affect energy metabolism and homeostasis of P...
February 27, 2017: Protein and Peptide Letters
Hailong Jiang, Dongsheng Che, Guixin Qin, Xiangjie Kong, Mohammed Hamdy Farouk
Non-fiber carbohydrates (NFC) have a crucial function on the gut health of monogastrics. This paper aims to review the relevant published materials on the influence of NFC's on the gut's microbial population and composition in monogastrics, and points out the areas of the required research. Total bacteria count and Lactobacillus sp. were decreased with an increase in composition of dietary NFC intake, as well as accompanied by a decrease in the short-chain fatty acids (SCFAs) levels. Consequently, some metabolites were affected by the accumulation of the bile acids, including molecules which control different gene expression levels, as regulators involved in glucose (FXR and TGR5) and fat metabolism (cholesterol)...
February 23, 2017: Protein and Peptide Letters
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