This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 19/6/1947    most recent tpc.107.051391v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via ISI Web of Science (13) Citing Articles via Google Scholar Google Scholar Articles by Baumann, M. J. Articles by Brumer, H. Search for Related Content PubMed PubMed Citation Articles by Baumann, M. J. Articles by Brumer, H., III Agricola Articles by Baumann, M. J. Articles by Brumer, H.

Structural Evidence for the Evolution of Xyloglucanase Activity from Xyloglucan Endo-Transglycosylases: Biological Implications for Cell Wall Metabolism^[W]

^a School of Biotechnology, Royal Institute of Technology, AlbaNova University Center, S-10691 Stockholm, Sweden
^b Equipe Glycobiologie Marine, Unité Mixte de Recherche 7139, Végétaux Marins et Biomolécules, Centre National de la Recherche Scientifique/Université Pierre et Marie Curie-Paris 6, Station Biologique, 29682 Roscoff, Bretagne, France

¹ To whom correspondence should be addressed. E-mail czjzek{at}sb-roscoff.fr or harry{at}biotech.kth.se; fax 33-298-292-324 or 46-8-5537-8367.

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 x Populus tremuloides). Production of the loop deletion variant Tm-NXG1-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.

This article has been cited by other articles:

				E. J. Mellerowicz, P. Immerzeel, and T. Hayashi Xyloglucan: The Molecular Muscle of Trees Ann. Bot., November 1, 2008; 102(5): 659 - 665. [Abstract] [Full Text] [PDF]

				K. Piens, R. Faure, G. Sundqvist, M. J. Baumann, M. Saura-Valls, T. T. Teeri, S. Cottaz, A. Planas, H. Driguez, and H. Brumer Mechanism-based Labeling Defines the Free Energy Change for Formation of the Covalent Glycosyl-enzyme Intermediate in a Xyloglucan endo-Transglycosylase J. Biol. Chem., August 8, 2008; 283(32): 21864 - 21872. [Abstract] [Full Text] [PDF]

				M. Saura-Valls, R. Faure, H. Brumer, T. T. Teeri, S. Cottaz, H. Driguez, and A. Planas Active-site Mapping of a Populus Xyloglucan endo-Transglycosylase with a Library of Xylogluco-oligosaccharides J. Biol. Chem., August 8, 2008; 283(32): 21853 - 21863. [Abstract] [Full Text] [PDF]

				V. Genovesi, S. Fornale, S. C. Fry, K. Ruel, P. Ferrer, A. Encina, F.-M. Sonbol, J. Bosch, P. Puigdomenech, J. Rigau, et al. ZmXTH1, a new xyloglucan endotransglucosylase/hydrolase in maize, affects cell wall structure and composition in Arabidopsis thaliana J. Exp. Bot., March 3, 2008; (2008) ern013v2. [Abstract] [Full Text] [PDF]