Structural Characterization and Directed Evolution of a Novel Acetyl Xylan Esterase Reveals Thermostability Determinants of the Carbohydrate Esterase 7 Family.

ABSTRACT: A hot desert hypolith metagenomic DNA sequence data set was screened in silico for genes annotated as acetyl xylan esterases (AcXEs). One of the genes identified encoded an ∼36-kDa protein (Axe1_NaM1). The synthesized gene was cloned and expressed, and the resulting protein was purified. NaM1 was optimally active at pH 8.5 and 30°C and functionally stable at salt concentrations of up to 5 M. The specific activity and catalytic efficiency were 488.9 U mg^-1 and 3.26 × 10⁶ M^-1 s^-1, respectively. The crystal structure of wild-type NaM1 was solved at a resolution of 2.03 Å, and a comparison with the structures and models of more thermostable carbohydrate esterase 7 (CE7) family enzymes and variants of NaM1 from a directed evolution ex

SUBMITTER: Adesioye FA 

PROVIDER: S-EPMC5881061 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature