| Autor: |
Baumann MJ; School of Biotechnology, Royal Institute of Technology, AlbaNova University Center, Stockholm, Sweden., Eklöf JM, Michel G, Kallas AM, Teeri TT, Czjzek M, Brumer H 3rd |
| Jazyk: |
angličtina |
| Zdroj: |
The Plant cell [Plant Cell] 2007 Jun; Vol. 19 (6), pp. 1947-63. Date of Electronic Publication: 2007 Jun 08. |
| DOI: |
10.1105/tpc.107.051391 |
| Abstrakt: |
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. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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