The mutation of Thr315 to Asn of GH10 xylanase XynR increases the alkaliphily but decreases the alkaline resistance. Issue 8 (2nd June 2021)

• Record Type: Journal Article
• Authors: Kuwata, Kohei; Suzuki, Manami; Takita, Teisuke; Yatsunami, Rie; Nakamura, Satoshi; Yasukawa, Kiyoshi
• Is Part Of: Bioscience, biotechnology, and biochemistry. Volume 85:Issue 8(2021)
• Page Start: 1853
• Page End: 1860
• Publication Date: 2021-06-02
• Subjects: GH10 -- alkaliphily -- alkaline resistance -- xylan -- xylanase; Biotechnology -- Periodicals; Biochemistry -- Periodicals; 660.6
• DOI: 10.1093/bbb/zbab102
• Languages: English
• ISSNs: 0916-8451

Abstract

ABSTRACT: XynR is a thermophilic and alkaline GH10 xylanase, identified in the culture broth of alkaliphilic and thermophilic Bacillus sp. strain TAR-1. We previously selected S92E as a thermostable variant from a site saturation mutagenesis library. Here, we attempted to select the alkaliphilic XynR variant from the library and isolated T315N. In the hydrolysis of beechwood xylan, T315N and S92E/T315N exhibited a broader bell-shaped pH-dependent activity than the wild-type (WT) XynR and S92E. The optimal pH values of T315N and S92E/T315N were 6.5-9.5 while those of WT and S92E were 6.5-8.5. On the other hand, T315N and S92E/T315N exhibited a narrower bell-shaped pH dependence of stability: the pHs at which the activity was stable after the incubation at 37 °C for 24 h were 6.0-8.5 for T315N and S92E/T315N, but 6.0-10.0 for WT and S92E. These results indicated that the mutation of Thr315 to Asn increased the alkaliphily but decreased the alkaline resistance. Graphical Abstract: