Biochemical and Structural Characterization of a Five-domain GH115 α-Glucuronidase from the Marine Bacterium Saccharophagus degradans 2-40 T
- Univ. of Toronto, ON (Canada)
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Chalmers Univ. of Technology, Gothenburg (Sweden)
- Chalmers Univ. of Technology, Gothenburg (Sweden); Univ. of Guadalajara (Mexico)
- Univ. of Helsinki (Finland)
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 - (132)-linked (Me)GlcAp side groups. Herein, a family GH115 enzyme from the marine bacterium Saccharophagus degradans 2-40T, 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.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Biological and Environmental Research (BER)
- DOE Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1336904
- Journal Information:
- Journal of Biological Chemistry, Vol. 291, Issue 27; ISSN 0021-9258
- Publisher:
- American Society for Biochemistry and Molecular Biology
- Country of Publication:
- United States
- Language:
- English
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