2UWB

Crystal structure of the Nasturtium seedling mutant xyloglucanase isoform NXG1-delta-YNIIG

Summary for 2UWB

• Entry DOI: 10.2210/pdb2uwb/pdb
• Related: 2UWA 2UWC
• Descriptor: CELLULASE (2 entities in total)
• Functional Keywords: xyloglucan-endo-transferase, glycoside hydrolase, loop mutant nxg1- yniig, hydrolase, glycosidase, family gh16, tropaeolum majus xyloglucanase
• Biological source: TROPAEOLUM MAJUS (NASTURTIUM)
• Total number of polymer chains: 2
• Total formula weight: 60909.15

Authors

Baumann, M.J.,Eklof, J.,Michel, G.,Kallasa, A.,Teeri, T.T.,Brumer, H.,Czjzek, M. (deposition date: 2007-03-20, release date: 2007-06-26, Last modification date: 2024-11-13)

Primary citation

Baumann, M.J.,Eklof, J.,Michel, G.,Kallasa, A.,Teeri, T.T.,Czjzek, M.,Brumer, H.
Structural Evidence for the Evolution of Xyloglucanase Activity from Xyloglucan Endo-Transglycosylases: Biological Implications for Cell Wall Metabolism.
Plant Cell, 19:1947-, 2007

PubMed Abstract: 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-DeltaYNIIG 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.

PubMed: 17557806
DOI: 10.1105/TPC.107.051391

Experimental method

X-RAY DIFFRACTION (2 Å)