Biochemical and Structural Characterization of a Five-domain GH115-Glucuronidase from the Marine Bacterium Saccharophagus degradans 2-40(T)
Artikel i vetenskaplig tidskrift, 2016

Glucuronic acid (GlcAp) and/or methylglucuronic acid (MeGlcAp) decorate the major forms of xylan in hardwood and coniferous softwoods as well as many cereal grains. Accordingly, the complete utilization of glucuronoxylans or conversion to sugar precursors requires the action of main chain xylanases as well as -glucuronidases that release the - (12)-linked (Me)GlcAp side groups. Herein, a family GH115 enzymefrom the marine bacterium Saccharophagus degradans 2-40(T), SdeAgu115A, demonstrated activity toward glucuronoxylan and oligomers thereof with preference toward MeGlcAp linked to internal xylopyranosyl residues. Unique biochemical characteristics of NaCl activation were also observed. The crystal structure of SdeAgu115A revealed a five-domain architecture, with an additional insertion C+ domain that had significant impact on the domain arrangement of SdeAgu115A monomer and its dimerization. The participation of domain C+ in substrate binding was supported by reduced substrate inhibition upon introducing W773A, W689A, and F696A substitutions within this domain. In addition to Asp-335, the catalytic essentiality of Glu-216 was revealed by site-specific mutagenesis. A primary sequence analysis suggested that the SdeAgu115A architecture is shared by more than half of GH115 members, thus defining a distinct archetype for GH115 enzymes.


enzyme structure

crystal structure

catalytic apparatus

enzyme domain composition

carbohydrate degradation

enzyme catalysis

protein domain



W. J. Wang

University of Toronto

R. Y. Yan

University of Toronto

B. P. Nocek

Argonne National Laboratory

T. V. Vuong

University of Toronto

R. Di Leo

University of Toronto

X. H. Xu

University of Toronto

H. Cui

University of Toronto

Paul Gatenholm

Wallenberg Wood Science Center (WWSC)

Chalmers, Kemi och kemiteknik, Tillämpad kemi

Guillermo Toriz Gonzalez

Chalmers, Kemi och kemiteknik, Tillämpad kemi

M. Tenkanen

Helsingin Yliopisto

A. Savchenko

University of Toronto

E. R. Master

Journal of Biological Chemistry

0021-9258 (ISSN) 1083-351X (eISSN)

Vol. 291 27 14120-14133


Biokemi och molekylärbiologi





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