Cloning, overexpression, and characterization of a novel alkali‐thermostable xylanase from Geobacillus sp. WBI. (18th November 2014)

• Record Type: Journal Article
• Authors: Mitra, Suranjita; Mukhopadhyay, Bidhan Chandra; Mandal, Anisur Rahaman; Arukha, Ananta Prasad; Chakrabarty, Kuheli; Das, Gourab Kanti; Chakrabartty, Pran Krishna; Biswas, Swadesh Ranjan
• Is Part Of: Journal of basic microbiology. Volume 55:issue 4(2015:Apr.)
• Page Start: 527
• Page End: 537
• Publication Date: 2014-11-18
• Subjects: Microbiology -- Periodicals; 579
• DOI: 10.1002/jobm.201400495
• Languages: English
• ISSNs: 0233-111X

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <sec id="jobm201400495-sec-0001" sec-type="section"> <p>An endo‐β‐1, 4‐xylanase gene <italic>xynA</italic> of a thermophilic <italic>Geobacillus</italic> sp. WBI from "hot" compost was isolated by PCR amplification. The gene encoding 407 residues were overexpressed in <italic>E. coli</italic> and purified by Ni‐NTA chromatography. The purified enzyme (47 kDa) had a broad pH optimum of 6.0 to 9.0, and was active between 50 and 90 °C. The enzyme retained 100% of its activity when incubated at 65 °C for 1 h under alkaline condition (pH 10.0) and retained 75% activity at pH 11.0. The <italic>K</italic><sub>m</sub> and <italic>V</italic><sub>max</sub> of the enzyme were 0.9 mg ml<sup>−1</sup> and 0.8 µmol ml<sup>−1</sup> min<sup>−1</sup>, respectively. In molecular dynamics simulation at 338 K (65 °C), the enzyme was found to be stable. At an elevated temperature (450 K) specific α‐helix and β‐turns of the proteins were most denatured. The denaturation was less in WBI compared with its highest homolog <italic>G. stearothermophilus</italic> T‐6 xylanase with difference of six residues. The results predict that these regions are responsible for the improved thermostability observed over related enzymes. The present work encourages further experimental demonstration to understand how these regions contribute thermostability to WBI xylanase. The study noted that WBI produces a xylanase with unique characteristics, specifically alkali‐thermostability.</p> </sec> </abstract>