NMR Spectroscopic Analysis Reveals Extensive Binding Interactions of Complex Xyloglucan Oligosaccharides with the Cellvibrio japonicus Glycoside Hydrolase Family 31 a-Xylosidase
2012 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, no 42, 13395-13404 p.Article in journal (Refereed) Published
The study of the interaction of glycoside hydrolases with their substrates is fundamental to diverse applications in medicine, food and feed production, and biomass-resource utilization. Recent molecular modeling of the a-xylosidase CjXyl31A from the soil saprophyte Cellvibrio japonicus, together with protein crystallography and enzyme-kinetic analysis, has suggested that an appended PA14 protein domain, unique among glycoside hydrolase family 31 members, may confer specificity for large oligosaccharide fragments of the ubiquitous plant polysaccharide xyloglucan (J. Larsbrink, A. Izumi, F. M. Ibatullin, A. Nakhai, H. J. Gilbert, G. J. Davies, H. Brumer, Biochem. J. 2011, 436, 567580). In the present study, a combination of NMR spectroscopic techniques, including saturation transfer difference (STD) and transfer NOE (TR-NOE) spectroscopy, was used to reveal extensive interactions between CjXyl31A active-site variants and xyloglucan hexa- and heptasaccharides. The data specifically indicate that the enzyme recognizes the entire cello-tetraosyl backbone of the substrate and product in positive enzyme subsites and makes further significant interactions with internal pendant a-(1?6)-linked xylosyl units. As such, the present analysis provides an important rationalization of previous kinetic data on CjXyl31A and unique insight into the role of the PA14 domain, which was not otherwise obtainable by protein crystallography.
Place, publisher, year, edition, pages
2012. Vol. 18, no 42, 13395-13404 p.
a-xylosidases, Cellvibrio japonicus, molecular recognition, mutagenesis, NMR spectroscopy, xyloglucan
IdentifiersURN: urn:nbn:se:kth:diva-105659DOI: 10.1002/chem.201200488ISI: 000309597000023OAI: oai:DiVA.org:kth-105659DiVA: diva2:572828
FunderSwedish Research Council
QC 201211292012-11-292012-11-232013-08-26Bibliographically approved