Bioinformatics Insights Into Microbial Xylanase Protein Sequences

Abstract

Microbial xylanases represents an industrially important group of enzymes associated with hydrolysis of xylan, a major hemicellulosic component of plant cell walls. A total of 122 protein sequences comprising of 58 fungal, 25 bacterial, 19actinomycetes and 20 yeasts xylanaseswere retrieved from NCBI, GenBank databases. These sequences were in-silico characterized for homology,sequence alignment, phylogenetic tree construction, motif assessment and physio-chemical attributes. The amino acid residues ranged from 188 to 362, molecular weights were in the range of 20.3 to 39.7 kDa and pI ranged from 3.93 to 9.69. The aliphatic index revealed comparatively less thermostability and negative GRAVY indicated that xylanasesarehydrophilicirrespective of the source organisms.Several conserved amino acid residues associated with catalytic domain of the enzyme were observed while different microbial sources also revealed few conserved amino acid residues. The comprehensive phylogenetic tree indicatedsevenorganismsspecific,distinct major clusters,designated as A, B, C, D, E, F and G. The MEME based analysis of 10 motifs indicated predominance of motifs specific to GH11 family and one of the motif designated as motif 3 with sequence GTVTSDGGTYDIYTTTRTNAP was found to be present in most of the xylanases irrespective of the sources.Sequence analysis of microbial xylanases provides an opportunity to develop strategies for molecular cloning and expression of xylanase genes and also foridentifying sites for genetic manipulation for developing novel xylanases with desired features as per industrial needs.