RRC ID 40980
Author Watanabe A, Hiraga K, Suda M, Yukawa H, Inui M.
Title Functional Characterization of Corynebacterium alkanolyticum β-Xylosidase and Xyloside ABC Transporter in Corynebacterium glutamicum.
Journal Appl Environ Microbiol
Abstract The Corynebacterium alkanolyticum xylEFGD gene cluster comprises the xylD gene that encodes an intracellular β-xylosidase next to the xylEFG operon encoding a substrate-binding protein and two membrane permease proteins of a xyloside ABC transporter. Cloning of the cluster revealed a recombinant β-xylosidase of moderately high activity (turnover for p-nitrophenyl-β-d-xylopyranoside of 111 ± 4 s(-1)), weak α-l-arabinofuranosidase activity (turnover for p-nitrophenyl-α-l-arabinofuranoside of 5 ± 1 s(-1)), and high tolerance to product inhibition (Ki for xylose of 67.6 ± 2.6 mM). Heterologous expression of the entire cluster under the control of the strong constitutive tac promoter in the Corynebacterium glutamicum xylose-fermenting strain X1 enabled the resultant strain X1EFGD to rapidly utilize not only xylooligosaccharides but also arabino-xylooligosaccharides. The ability to utilize arabino-xylooligosaccharides depended on cgR_2369, a gene encoding a multitask ATP-binding protein. Heterologous expression of the contiguous xylD gene in strain X1 led to strain X1D with 10-fold greater β-xylosidase activity than strain X1EFGD, albeit with a total loss of arabino-xylooligosaccharide utilization ability and only half the ability to utilize xylooligosaccharides. The findings suggest some inherent ability of C. glutamicum to take up xylooligosaccharides, an ability that is enhanced by in the presence of a functional xylEFG-encoded xyloside ABC transporter. The finding that xylEFG imparts nonnative ability to take up arabino-xylooligosaccharides should be useful in constructing industrial strains with efficient fermentation of arabinoxylan, a major component of lignocellulosic biomass hydrolysates.
Volume 81(12)
Pages 4173-83
Published 2015-6-15
DOI 10.1128/AEM.00792-15
PII AEM.00792-15
PMID 25862223
PMC PMC4524156
MeSH ATP-Binding Cassette Transporters / genetics* ATP-Binding Cassette Transporters / metabolism* Amino Acid Sequence Bacterial Proteins / genetics Carrier Proteins / genetics Cloning, Molecular Corynebacterium / enzymology* Corynebacterium / genetics* Corynebacterium / growth & development Corynebacterium / metabolism Corynebacterium glutamicum / enzymology* Corynebacterium glutamicum / genetics* Corynebacterium glutamicum / growth & development Corynebacterium glutamicum / metabolism Fermentation Glucuronates / metabolism Glycoside Hydrolases / metabolism Glycosides / metabolism* Kinetics Molecular Sequence Data Multigene Family Oligosaccharides / metabolism Operon Xylans / metabolism Xylose / metabolism Xylosidases / genetics Xylosidases / metabolism*
IF 4.016
Times Cited 9
General Microbes JCM 18229