FUNCTIONAL INSIGHTS AND MOLECULAR MODEL ANALYSES OF Thermotoga maritima XYLANASES REVEAL THERMOSTABILITY AND COMPLEX EVOLUTIONARY LINEAGE

Thermotoga maritima derived xylanases are important industrial enzymes owing to extensive thermotolerance and stability under broad pH range This study presents in-silico characterization of Thermotoga maritima derived xylanase A and xylanase B through homology modeling and molecular docking approaches. Analyses of primary and secondary structures revealed net negative charges on both xylanase A and xylanase B. Modular structure of xylanase A exhibited five significant domains including two CBM49, one GlycoHydro10 and two DUF1083. Whereas, structure of xylanase B contained one significant domain i.e. Glyco hydro 10. The amino acid residues Leu-54, Arg-85, Leu-66, Phe-68, Asn-81 and Ile-52 of CBM49 have shown interaction with xylan during docking analyses. Within second CBM49 domain, Tyr-96, Trp-47 and Arg-19 have shown interaction with xylan. No residue of GlycoHydro10 was found to interact with xylan. Whereas, Asn-55, Arg-83, Arg-60 and ILe-118 of DUF1083 interacted with xylan. The Phe-170, Trp-156, Glu-15, Ser-157 and Lys-17 of DUF-1083 domain of xylanase A also showed interaction with xylan. The Glu-15 and Phe-170 of xylanase B showed H-bonding while Lys-565 showed electrostatic interaction with xylan. Comparative phylogenetic analysis of xylanases from Thermotoga genus, showed the complex evolutionary lineage of multimeric xylanase A protein. The findings of this study will lead us towards functional insights of xylanases from Thermotoga maritima and will help the researchers in xylanase enzyme engineering through rational design for developing highly efficient industrial enzymes