Crystal Structures of a Poplar Xyloglucan Endotransglycosylase Reveal Details of Transglycosylation Acceptor Binding
| Autor: | Hongbin Henriksson, Tuula T. Teeri, Patrik Johansson, Martin J. Baumann, Harry Brumer, T. Alwyn Jones, Stuart E. Denman, Åsa M. Kallas |
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| Rok vydání: | 2004 |
| Předmět: |
Models
Molecular Glycosylation Protein Conformation Molecular Sequence Data Oligosaccharides Plant Science Biology Crystallography X-Ray Pichia Pichia pastoris Cell wall chemistry.chemical_compound Protein structure Glycoside hydrolase Amino Acid Sequence Binding site Glucans Research Articles chemistry.chemical_classification Binding Sites Sequence Homology Amino Acid Glycosyltransferases Glycosidic bond Cell Biology biology.organism_classification Recombinant Proteins Xyloglucan Populus Carbohydrate Sequence chemistry Biochemistry Xylans |
| Zdroj: | The Plant Cell. 16:874-886 |
| ISSN: | 1532-298X 1040-4651 |
| DOI: | 10.1105/tpc.020065 |
| Popis: | Xyloglucan endotransglycosylases (XETs) cleave and religate xyloglucan polymers in plant cell walls via a transglycosylation mechanism. Thus, XET is a key enzyme in all plant processes that require cell wall remodeling. To provide a basis for detailed structure-function studies, the crystal structure of Populus tremula x tremuloides XET16A (PttXET16A), heterologously expressed in Pichia pastoris, has been determined at 1.8-A resolution. Even though the overall structure of PttXET16A is a curved beta-sandwich similar to other enzymes in the glycoside hydrolase family GH16, parts of its substrate binding cleft are more reminiscent of the distantly related family GH7. In addition, XET has a C-terminal extension that packs against the conserved core, providing an additional beta-strand and a short alpha-helix. The structure of XET in complex with a xyloglucan nonasaccharide, XLLG, reveals a very favorable acceptor binding site, which is a necessary but not sufficient prerequisite for transglycosylation. Biochemical data imply that the enzyme requires sugar residues in both acceptor and donor sites to properly orient the glycosidic bond relative to the catalytic residues. |
| Databáze: | OpenAIRE |
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