Your browser version may not work well with NCBI's Web applications. More information here...
1: Plant Cell. 2007 Jun;19(6):1947-63. Epub 2007 Jun 8.
Related Articles, Links
Click here to read Click here to read Click here to read
Structural evidence for the evolution of xyloglucanase activity from xyloglucan endo-transglycosylases: biological implications for cell wall metabolism.

Baumann MJ, Eklöf JM, Michel G, Kallas AM, Teeri TT, Czjzek M, Brumer H 3rd.

School of Biotechnology, Royal Institute of Technology, AlbaNova University Center, Stockholm, Sweden.

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.

Publication Types:
PMID: 17557806 [PubMed - indexed for MEDLINE]

PMCID: PMC1955714