Elucidation of structural and functional integration of a novel antimicrobial peptide from Antheraea mylitta.

We report here the amino acid sequence of an antimicrobial peptide of Antheraea mylitta (peptide fraction II) effectively killed urinary tract associated MDR E. coli (Dutta et al., 2016), as Gly-Gly-Gly-Gly-Gly-Gly-His-Leu-Val-Ala. The physicochemical and biological properties of this peptide were evaluated by computational analysis and its isoelectric point, grand average of hydropathicity and Boman index values were found to be 6.74, 0.42 and -1.17kcal/mol, respectively. One valid model of peptide fraction II was constructed, that contains two antiparallel ß sheets with a hairpin and appeared as 'U' shaped structure. The glycine rich composition (Gly1, Gly5, Gly6 and Ala10) facilitates mostly for its flexibility or dynamicity, and in its other wing, aggregation prone residues (Leu8, Val9, Ala10) triggered its auto-aggregations when contacted only with the microbial membrane. We employed simulation of peptide binding on the membrane, showed stable and deep insertion of peptide fraction II into the membrane through its hydrophobic tail (up to 3.3±1.46Å). Molecular docking study with Patchdock server revealed that this peptide could interact with the lipid aliphatic chain of 1-palmitoyl-2-oleoyl-phosphoethanolamine (POPE) bilayer and may linked to membrane distortion as we have reported earlier. Further, the studied peptide has been predicted not to exhibit any antigenicity and non-responsive to RBC membrane. These data for the first time provide new insights of an antimicrobial peptide from silkworm A. mylitta and it may serve as the template for the design of novel peptide antibiotics from this group of insect against MDR Gram-negative bacteria.

Evaluation of substrate specificity and catalytic promiscuity of Bacillus albus cellulase: an insight into in silico proteomic study aiming at enhanced production of renewable energy.

Cellulases are enzymes that aid in the hydrolysis of cellulosic fibers and have a wide range of industrial uses. In the present in silico study, sequence alignment between cellulases from different Bacillus species revealed that most of the residues are conserved in those aligned enzymes. Three dimensional structures of cellulase enzymes from 23 different Bacillus species have been predicted and based on the alignment between the modeled structures, those enzymes have been categorized into 7 different groups according to the homology in their conformational folds. There are two structural contents in Gr-I cellulase namely ß1-α2 and ß3-α5 loops which varies greatly according to their static position. Molecular docking study between the B. albus cellulase and its various cellulosic substrates including xylanoglucan oligosaccharides revealed that residues viz. Phe154, Tyr258, Tyr282, Tyr285, and Tyr376 of B. albus cellulase are significantly involved in formation stacking interaction during enzyme-substrate binding. Residue interaction network and binding energy analysis for the B. albus cellulase with different cellulosic substrates depicted the strong affinity of XylGlc3 substrate with the receptor enzyme. Molecular interaction and molecular dynamics simulation studies exhibited structural stability of enzyme-substrate complexes which are greatly influenced by the presence of catalytic promiscuity in their substrate binding sites. Screening of B. albus in carboxymethylcellulose (CMC) and xylan supplemented agar media revealed the capability of the bacterium in degrading both cellulose and xylan. Overall, the study demonstrated B. albus cellulase as an effective biocatalyst candidate with the potential role of catalytic promiscuity for possible applications in biofuel industries.Communicated by Ramaswamy H. Sarma.

Some Functional Properties of khambir, an Ethnic Fermented Cereal-Based Food of Western Himalayas.

Traditional leavened wheat-based flat bread khambir is a staple food for the high-altitude people of the Western Himalayan region. The health promoting abilities of two types of khambir, yeast added khambir (YAK) and buttermilk added khambir (BAK), were evaluated. A group of microbes like yeast, mold, lactic acid bacteria (LAB), and Bifidobacterium sp. were abundant in both khambir but in varied proportions. Both are enriched with phenolics and flavonoids. The aqueous extracts of both breads strongly inhibited the growth of enteropathogens. Molecular docking experiments showed that phenolic acid, particularly p-coumaric acid, blocked the active sites of ß-glucosidase and acetylcholine esterase (AChE), thereby inhibiting their activities. YAK and BAK showed antiradical and antioxidant activity ranging from 46 to 67% evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), and ferric reducing/antioxidant power (FRAP) assays. The aqueous extract of both khambir samples protected the arsenic toxicity when examined under an in situ rat intestinal loop model study. The arsenic induced elevated levels of superoxide dismutase (SOD), catalase (CAT), reduced glutathione, lipid peroxidation (LPO) and DNA fragmentation, and transmembrane mitochondrial potential was alleviated by khambir extract. These results scientifically supported its age-old health benefit claims by the consumer at high altitude and there are enough potentialities to explore khambir as a medicinal food for human welfare.

Production of α-Amylase by Aspergillus terreus NCFT 4269.10 Using Pearl Millet and Its Structural Characterization.

In this investigation, Aspergillus terreus NCFT4269.10 was employed in liquid static surface (LSSF) and solid state (SSF) fermentation to assess the optimal conditions for α-amylase biosynthesis. One-variable-at-a-time approach (quasi-optimum protocol) was primarily used to investigate the effect of each parameter on production of amylase. The maximum amylase production was achieved using pearl millet (PM) as substrate by SSF (19.19 ± 0.9 Ug(-1)) and also in presence of 1 mM magnesium sulfate, 0.025% (w/v) gibberellic acid, and 30 mg/100 ml (w/v) of vitamin E (~60-fold higher production of amylase) with the initial medium pH of 7.0 and incubation at 30 °C for 96 h. In addition, maltose, gelatin and isoleucine also influenced the α-amylase production. Amylase was purified to homogeneity with molecular mass around 15.3 kDa. The enzyme comprised of a typical secondary structure containing α-helix (12.2%), ß-pleated sheet (23.6%), and ß-turn (27.4%). Exploitation of PM for α-amylase production with better downstream makes it the unique enzyme for various biotechnological applications.