Structural evidence for the evolution of xyloglucanase activity from xyloglucan endo-transglycosylases: Biological implications for cell wall metabolism
2007 (English)In: The Plant Cell, ISSN 1040-4651, E-ISSN 1532-298X, Vol. 19, no 6, 1947-1963 p.Article in journal (Refereed) Published
High-resolution, three-dimensional structures of the archetypal glycoside hydrolase family 16 (GH16) endo-xyloglucanases Tm-NXG1 and Tm-NXG2 from nasturtium (Tropaeolum majus) have been solved by x-ray crystallography. Key structural features that modulate the relative rates of substrate hydrolysis to transglycosylation in the GH16 xyloglucan-active enzymes were identified by structure-function studies of the recombinantly expressed enzymes in comparison with data for the strict xyloglucan endo-transglycosylase Ptt-XET16-34 from hybrid aspen ( Populus tremula 3 Populus tremuloides). Production of the loop deletion variant Tm-NXG1-Delta YNIIG yielded an enzyme that was structurally similar to Ptt- XET16-34 and had a greatly increased transglycosylation: hydrolysis ratio. Comprehensive bioinformatic analyses of XTH gene products, together with detailed kinetic data, strongly suggest that xyloglucanase activity has evolved as a gain of function in an ancestral GH16 XET to meet specific biological requirements during seed germination, fruit ripening, and rapid wall expansion.
Place, publisher, year, edition, pages
2007. Vol. 19, no 6, 1947-1963 p.
tropaeolum-majus l, germinated nasturtium seeds, glycoside hydrolases, expression analysis, kappa-carrageenase, sequence alignment, crystal-structures, pichia-pastoris, hybrid aspen, endotransglycosylase
Biochemistry and Molecular Biology
IdentifiersURN: urn:nbn:se:kth:diva-16832DOI: 10.1105/tpc.107.051391ISI: 000248451900017ScopusID: 2-s2.0-34547657101OAI: oai:DiVA.org:kth-16832DiVA: diva2:334875
QC 201005252010-08-052010-08-052011-04-01Bibliographically approved