1jgi: Difference between revisions
No edit summary |
No edit summary |
||
| Line 1: | Line 1: | ||
[[Image:1jgi.jpg|left|200px]] | [[Image:1jgi.jpg|left|200px]] | ||
<!-- | |||
The line below this paragraph, containing "STRUCTURE_1jgi", creates the "Structure Box" on the page. | |||
You may change the PDB parameter (which sets the PDB file loaded into the applet) | |||
or the SCENE parameter (which sets the initial scene displayed when the page is loaded), | |||
or leave the SCENE parameter empty for the default display. | |||
| | --> | ||
| | {{STRUCTURE_1jgi| PDB=1jgi | SCENE= }} | ||
}} | |||
'''Crystal Structure of the Active Site Mutant Glu328Gln of Amylosucrase from Neisseria polysaccharea in Complex with the Natural Substrate Sucrose''' | '''Crystal Structure of the Active Site Mutant Glu328Gln of Amylosucrase from Neisseria polysaccharea in Complex with the Natural Substrate Sucrose''' | ||
| Line 29: | Line 26: | ||
[[Category: Mirza, O.]] | [[Category: Mirza, O.]] | ||
[[Category: Skov, L K.]] | [[Category: Skov, L K.]] | ||
[[Category: | [[Category: Active site mutant glu328gln]] | ||
[[Category: | [[Category: Sucrose complex]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 21:11:44 2008'' | |||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | |||
Revision as of 21:11, 2 May 2008
Crystal Structure of the Active Site Mutant Glu328Gln of Amylosucrase from Neisseria polysaccharea in Complex with the Natural Substrate Sucrose
OverviewOverview
The structure of amylosucrase from Neisseria polysaccharea in complex with beta-D-glucose has been determined by X-ray crystallography at a resolution of 1.66 A. Additionally, the structure of the inactive active site mutant Glu328Gln in complex with sucrose has been determined to a resolution of 2.0 A. The D-glucose complex shows two well-defined D-glucose molecules, one that binds very strongly in the bottom of a pocket that contains the proposed catalytic residues (at the subsite -1), in a nonstrained (4)C(1) conformation, and one that binds in the packing interface to a symmetry-related molecule. A third weaker D-glucose-binding site is located at the surface near the active site pocket entrance. The orientation of the D-glucose in the active site emphasizes the Glu328 role as the general acid/base. The binary sucrose complex shows one molecule bound in the active site, where the glucosyl moiety is located at the alpha-amylase -1 position and the fructosyl ring occupies subsite +1. Sucrose effectively blocks the only visible access channel to the active site. From analysis of the complex it appears that sucrose binding is primarily obtained through enzyme interactions with the glucosyl ring and that an important part of the enzyme function is a precise alignment of a lone pair of the linking O1 oxygen for hydrogen bond interaction with Glu328. The sucrose specificity appears to be determined primarily by residues Asp144, Asp394, Arg446, and Arg509. Both Asp394 and Arg446 are located in an insert connecting beta-strand 7 and alpha-helix 7 that is much longer in amylosucrase compared to other enzymes from the alpha-amylase family (family 13 of the glycoside hydrolases).
About this StructureAbout this Structure
1JGI is a Single protein structure of sequence from Neisseria polysaccharea. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structures of amylosucrase from Neisseria polysaccharea in complex with D-glucose and the active site mutant Glu328Gln in complex with the natural substrate sucrose., Mirza O, Skov LK, Remaud-Simeon M, Potocki de Montalk G, Albenne C, Monsan P, Gajhede M, Biochemistry. 2001 Jul 31;40(30):9032-9. PMID:11467966 Page seeded by OCA on Fri May 2 21:11:44 2008