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Papri Basak, Susmita Maitra-Majee, Jayanta Kumar Das, Abhishek Mukherjee, Shubhra Ghosh Dastidar, Pabitra Pal Choudhury, Arun Lahiri Majumder
A molecular evolutionary analysis of a well conserved protein helps to determine the essential amino acids in the core catalytic region. Based on the chemical properties of amino acid residues, phylogenetic analysis of a total of 172 homologous sequences of a highly conserved enzyme, L-myo-inositol 1-phosphate synthase or MIPS from evolutionarily diverse organisms was performed. This study revealed the presence of six phylogenetically conserved blocks, out of which four embrace the catalytic core of the functional protein...
2017: PloS One
K Walkowiak-Nowicka, G Nowicki, M Kuczer, G Rosiński
In insects, two types of the immune responses, cellular and humoral, constitute a defensive barrier against various parasites and pathogens. In response to pathogens, insects produce a wide range of immune agents that act on pathogens directly, such as cecropins or lysozyme, or indirectly by the stimulation of hemocyte migration or by increasing phenoloxidase (PO) activity. Recently, many new immunologically active substances from insects, such as peptides and polypeptides, have been identified. Nevertheless, in the most cases, their physiological functions are not fully known...
September 12, 2017: Bulletin of Entomological Research
Agnieszka Hernik-Magoń, Bartłomiej Fedorczyk, Robert Dec, Wojciech Puławski, Aleksandra Misicka, Wojciech Dzwolak
Several homopolypeptides including poly-l-glutamic acid (PLGA) form amyloid-like fibrils under favorable physicochemical conditions. We have shown recently that even short uncapped (Glu)n peptides (for n>3) form fibrillar β-aggregates which cross-seed with amyloid fibrils obtained from high molecular weight fractions of PLGA. Here we investigate effects of N-terminal acetylation and C-terminal amidation on the amyloidogenic tendencies of (Glu)n peptides containing 3, 4, and 5 residues. Our results based primarily on time-lapse FT-IR spectroscopy and AFM microscopy indicate that selective modifications of C-termini (and, to a lesser degree, of N-termini) decrease capacity of tetra- and pentapeptides to form fibrils...
September 1, 2017: Colloids and Surfaces. B, Biointerfaces
Yi-Wei Huang, Yu Wang, Yun Lin, Chin Lin, Yi-Tsung Lin, Cheng-Chih Hsu, Tsuey-Ching Yang
Penicillin binding proteins (PBPs) are involved in peptidoglycan synthesis, and their inactivation is linked to β-lactamase expression in ampR-β-lactamase module-harboring Gram-negative bacteria. There are seven annotated PBP genes, namely, mrcA, mrcB, pbpC, mrdA, ftsI, dacB, and dacC, in the Stenotrophomonas maltophilia genome, and these genes encode PBP1a, PBP1b, PBP1c, PBP2, PBP3, PBP4, and PBP6, respectively. In addition, S. maltophilia harbors two β-lactamase genes, L1 and L2, whose expression is induced via β-lactam challenge...
July 2017: MSystems
Laura A Antonaru, Dennis J Nürnberg
Cell differentiation is one of the marks of multicellular organisms. Terminally specialised nitrogen-fixing cells, termed heterocysts, evolved in filamentous cyanobacteria more than 2 Gya. The development of their spacing pattern has been thoroughly investigated in model organisms such as Anabaena sp. PCC 7120. This paper focuses on the more complex, branching cyanobacterium Mastigocladus laminosus (Stigonematales). Contrary to what has been previously published, a heterocyst spacing pattern is present in M...
August 15, 2017: FEMS Microbiology Letters
Marta De Zotti, Karen Wright, Edouard d'Aboville, Antonio Toffoletti, Claudio Toniolo, Giovanna Longhi, Giuseppe Mazzeo, Sergio Abbate, Fernando Formaggio
The intrinsically blue-colored Ullman imidazolinyl nitronyl nitroxide (NN) mono-radicals have found various applications, in particular as spin probes and organic magnetic materials. Here, we present the solution-phase synthesis, extensive characterization, and conformational analysis of the first peptidomimetics with two pendant, chiral nitronyl nitroxide free radical units. Two (R)-Aic(NN) residues, where Aic(NN) is 2-amino-5-nitronylnitroxide-indan-2-carboxylic acid, have been inserted at positions i and i+3 of the pentapeptide Boc-(R)-Aic(NN)-(Ala)2-(R)-Aic(NN)-Ala-OMe and the hexapeptide Boc-[Ala-(R)-Aic(NN)-Ala]2-OMe as well...
September 18, 2017: Journal of Organic Chemistry
Zexin Zhao, Shulin Hou, Dongming Lan, Xiumei Wang, Jinsong Liu, Faez Iqbal Khan, Yonghua Wang
MAS1 from marine Streptomyces sp. strain W007 belongs to the bacterial lipase I.7 subfamily and is characterized as a thermostable and nonregiospecific lipase. To shed light on the catalytic mechanism of MAS1, we determined its crystal structure with closed conformation in two crystal forms at 2.3 Å resolution. MAS1 adopts the canonical α/β hydrolase core fold with its catalytic triad being formed by S109, D200 and H232. Structural analysis and biochemical assays revealed that disulfide bonds and salt bridges play a vital role in the thermostability of MAS1...
August 31, 2017: FEBS Journal
Na Sun, Pengbo Cui, Dongmei Li, Ziqi Jin, Shuyu Zhang, Songyi Lin
A novel peptide from egg white, Asp-His-Thr-Lys-Glu (DHTKE), contains specific amino acids associated with iron binding. The present study aims to better understand the molecular basis of interactions between the DHTKE peptide and iron ions. The ultraviolet-visible and fluorescence spectra indicate an interaction between the DHTKE peptide and iron ions, which leads to the formation of a DHTKE-iron complex. Notably, Asp, Glu, His, and Lys in the DHTKE peptide play crucial roles in the formation of the DHTKE-iron complex, and the iron-binding site of the DHTKE peptide corresponds primarily to the amide and carboxyl groups...
September 20, 2017: Food & Function
Taiki Kuribara, Toshihiro Ishihara, Takaya Kudo, Makoto Hirano, Kiichiro Totani
Peptide:N-glycanase is a deglycosylation enzyme releasing N-glycan from glycoproteins. Although glycan specificity analysis of this enzyme has been reported, recognition requirements for the peptide sequence have not been precisely elucidated. Therefore, in this study, we carried out peptide specificity analysis of several peptide:N-glycanases. Using synthetic chitobiose-pentapeptide substrates having a systematic series of amino acid sequences composed of hydrophobic leucine and hydrophilic serine, we examined the peptide specificities of peptide:N-glycanases comprising yeast cytoplasmic PNGase, bacterial PNGase F, and plant PNGase A by ultra-performance liquid chromatography combined with electrospray ionization mass spectrometry...
August 18, 2017: Protein and Peptide Letters
Long Ding, Liying Wang, Zhipeng Yu, Sitong Ma, Zhiyang Du, Ting Zhang, Jingbo Liu
The objective of this paper was to investigate the effects of terminal amino acids on the transport of oligopeptides across the Caco-2 cell monolayer. Ala-based tetra- and pentapeptides were designed, and the N- or C-terminal amino acid residues were replaced by different amino acids. The results showed that the oligopeptides had a wide range of transport permeability across the Caco-2 cell monolayer and could be divided into four categories: non-/poor permeability, low permeability, intermediate permeability, and good permeability...
September 6, 2017: Journal of Agricultural and Food Chemistry
Caio César Sestile, Jhonatan Christian Maraschin, Marcel Pereira Rangel, Rosangela Getirana Santana, Hélio Zangrossi, Frederico Guilherme Graeff, Elisabeth Aparecida Audi
Reported results have shown that the pentapeptide opiorphin inhibits oligopeptidases that degrade brain neuropeptides, and has analgesic and antidepressant effects in experimental animals, without either tolerance or dependency after chronic administration. In a previous study we showed that opiorphin has a panicolytic-like effect in the dorsal periaqueductal gray (dPAG) electrical stimulation test (EST), mediated by the μ-opioid receptor (MOR). This study further analyzes the mechanism of opiorphin panicolytic action, using the EST and drug injection inside the dPAG...
October 3, 2017: Progress in Neuro-psychopharmacology & Biological Psychiatry
Narendra Kumar Mishra, Alok Jain, Christine Peter, Sandeep Verma
A controlled route toward biocompatible nanostructures has immense relevance for drug delivery and tissue engineering. We present an experimental-computational study identifying factors that govern the formation of well-defined aggregates by self-assembled pentapeptides, using single amino acid substitution. A subtle interplay between peptide rigidity/flexibility, hydrogen-bonding capacity, partitioning of aromatic side chains, and influence of dimerization determines the formation of ordered and disordered aggregate structures, and shifts the balance between the emergence of spherical or ill-defined morphologies...
August 18, 2017: Journal of Physical Chemistry. B
Tobin J Verbeke, Richard J Giannone, Dawn M Klingeman, Nancy L Engle, Thomas Rydzak, Adam M Guss, Timothy J Tschaplinski, Steven D Brown, Robert L Hettich, James G Elkins
This corrects the article DOI: 10.1038/srep43355.
July 27, 2017: Scientific Reports
Judit Ribera, Mónica Estupiñán, Alba Fuentes, Amanda Fillat, Josefina Martínez, Pilar Diaz
A search for extremophile enzymes from ancient volcanic soils in El Hierro Island (Canary Islands, Spain) allowed isolation of a microbial sporulated strain collection from which several enzymatic activities were tested. Isolates were obtained after sample cultivation under several conditions of nutrient contents and temperature. Among the bacterial isolates, supernatants from the strain designated JR3 displayed high esterase activity at temperatures ranging from 30 to 100°C, suggesting the presence of at least a hyper-thermophilic extracellular lipase...
2017: PloS One
Magdalena Wysocka, Kamila Sychowska, Natalia Gruba, Łukasz Winiarski, Marcin Skoreński, Mateusz Psurski, Joanna Makowska, Artur Giełdoń, Tomasz Wenta, Mirosław Jarząb, Przemysław Glaza, Joanna Zdancewicz, Marcin Sieńczyk, Barbara Lipińska, Adam Lesner
Herein, we report selection, synthesis, and enzymatic evaluation of a peptidomimetic library able to increase proteolytic activity of HtrA3 (high temperature requirement A) protease. Iterative deconvolution in solution of synthesized modified pentapeptides yielded two potent HtrA3 activators acting in the micromolar range (HCOO-CH2O-C6H4-OCH2-CO-Tyr-Asn-Phe-His-Asn-OH and HCOO-CH2O-C6H4-OCH2-CO-Tyr-Asn-Phe-His-Glu-OH). Both compounds increased proteolysis of an artificial HtrA3 substrate over 40-fold in a selective manner...
August 24, 2017: ACS Combinatorial Science
Sun-Young Park, Hyung-Hoon Oh, Young-Lan Park, Hyung-Min Yu, Dae-Seong Myung, Sung-Bum Cho, Wan-Sik Lee, Daeho Park, Young-Eun Joo
Malformin A1 (MA1), a cyclic pentapeptide isolated from Aspergillus niger, has been found to possess a range of bioactive properties including antibacterial activity. However, it is unclear whether MA1 exerts an anticancer effect or not. In this study, we conducted in vitro experiments to investigate its anticancer properties in human colorectal cancer cells. The effect of MA1 on human colorectal cancer cells, SW480 and DKO1, was examined by the WST-1 cell viability assay, inverted microscopy, 5-bromo-2-deoxyuridine (BrdU) incorporation, flow cytometry, DNA fragmentation, wound healing, Transwell assays, and western blotting...
July 10, 2017: International Journal of Oncology
Sneha Dutta, Anasuya Moitra, Debanjan Mukherjee, Gotam K Jarori
Plasmodium falciparum enolase (Pfeno) is a dimeric enzyme with multiple moonlighting functions. This enzyme is thus a potential target for anti-malarial treatments. A unique feature of Pfeno is the presence of a pentapeptide insert (104) EWGWS (108). The functional role of tryptophan residues in this insert was investigated using site-directed mutagenesis. Replacement of these two Trp residues with alanines (or lysines) resulted in a near complete loss of enolase activity and dissociation of the normal dimeric form into monomers...
July 2017: FEBS Open Bio
Wei Gao, Xiucong Yang, Zhiqiang Lin, Bing He, Dong Mei, Dan Wang, Haoran Zhang, Hua Zhang, Wenbing Dai, Xueqing Wang, Qiang Zhang
Cell-penetrating peptides (CPPs) are increasingly important in transporting macromolecules across cell membranes, but their use remains confined to narrow clinical applications due to the systemic toxicity induced by their positive charges. Several newly discovered electronic neutral penetrating peptides are not attracting much attention because their penetrating capacity is normally far less powerful than cationic or amphiphilic CPPs. In this study, we found the electronic neutral cyclic peptide cyclosporin A (CsA) exhibited 5...
September 10, 2017: Journal of Controlled Release: Official Journal of the Controlled Release Society
Claudiu N Lungu, Mircea V Diudea, Mihai V Putz
Docking-i.e., interaction of a small molecule (ligand) with a proteic structure (receptor)-represents the ground of drug action mechanism of the vast majority of bioactive chemicals. Ligand and receptor accommodate their geometry and energy, within this interaction, in the benefit of receptor-ligand complex. In an induced fit docking, the structure of ligand is most susceptible to changes in topology and energy, comparative to the receptor. These changes can be described by manifold hypersurfaces, in terms of polynomial discriminant and Laplacian operator...
June 27, 2017: International Journal of Molecular Sciences
Haiying Cai, Minjie Zhao, Yang Li, Jianwei Mao, Chenggang Cai, Fengqin Feng
BACKGROUND: Propeptides of lipases have been demonstrated to influence many properties of their mature proteins as intramolecular chaperones. However, the working mechanism of propeptides may be different. OBJECTIVES: The main objective of this study was to determine the role of pentapeptide prosequence of Thermomyces lanuginosus lipase (TLL) through its effect on the recombinant expression of TLL in P. pastoris, and explore the possible function mechanism with its hydrophobicity...
2017: Protein and Peptide Letters
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