1umz
From Proteopedia
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==Overview== | ==Overview== | ||
| - | Xyloglucan endotransglycosylases (XETs) cleave and religate xyloglucan | + | 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. |
==About this Structure== | ==About this Structure== | ||
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[[Category: Xyloglucan:xyloglucosyl transferase]] | [[Category: Xyloglucan:xyloglucosyl transferase]] | ||
[[Category: Brumer, H.]] | [[Category: Brumer, H.]] | ||
| - | [[Category: Denman, S | + | [[Category: Denman, S E.]] |
[[Category: Henriksson, H.]] | [[Category: Henriksson, H.]] | ||
[[Category: Johansson, P.]] | [[Category: Johansson, P.]] | ||
| - | [[Category: Jones, T | + | [[Category: Jones, T A.]] |
| - | [[Category: Kallas, A | + | [[Category: Kallas, A M.]] |
| - | [[Category: Teeri, T | + | [[Category: Teeri, T T.]] |
[[Category: glycoside hydrolase]] | [[Category: glycoside hydrolase]] | ||
[[Category: glycosyltransferase]] | [[Category: glycosyltransferase]] | ||
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[[Category: xyloglucan]] | [[Category: xyloglucan]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:26:19 2008'' |
Revision as of 13:26, 21 February 2008
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XYLOGLUCAN ENDOTRANSGLYCOSYLASE IN COMPLEX WITH THE XYLOGLUCAN NONASACCHARIDE XLLG.
Overview
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.
About this Structure
1UMZ is a Single protein structure of sequence from Populus tremula. Active as Xyloglucan:xyloglucosyl transferase, with EC number 2.4.1.207 Known structural/functional Site: . Full crystallographic information is available from OCA.
Reference
Crystal structures of a poplar xyloglucan endotransglycosylase reveal details of transglycosylation acceptor binding., Johansson P, Brumer H 3rd, Baumann MJ, Kallas AM, Henriksson H, Denman SE, Teeri TT, Jones TA, Plant Cell. 2004 Apr;16(4):874-86. Epub 2004 Mar 12. PMID:15020748
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