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1eyj
From Proteopedia
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[[Image:1eyj.jpg|left|200px]] | [[Image:1eyj.jpg|left|200px]] | ||
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'''FRUCTOSE-1,6-BISPHOSPHATASE COMPLEX WITH AMP, MAGNESIUM, FRUCTOSE-6-PHOSPHATE AND PHOSPHATE (T-STATE)''' | '''FRUCTOSE-1,6-BISPHOSPHATASE COMPLEX WITH AMP, MAGNESIUM, FRUCTOSE-6-PHOSPHATE AND PHOSPHATE (T-STATE)''' | ||
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[[Category: Choe, J.]] | [[Category: Choe, J.]] | ||
[[Category: Honzatko, R B.]] | [[Category: Honzatko, R B.]] | ||
| - | [[Category: | + | [[Category: Allosteric enzyme]] |
| - | [[Category: | + | [[Category: Bisphosphatase]] |
| - | [[Category: | + | [[Category: Gluconeogenesis]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 15:40:29 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 12:40, 2 May 2008
FRUCTOSE-1,6-BISPHOSPHATASE COMPLEX WITH AMP, MAGNESIUM, FRUCTOSE-6-PHOSPHATE AND PHOSPHATE (T-STATE)
Overview
Crystal structures of metal-product complexes of fructose 1, 6-bisphosphatase (FBPase) reveal competition between AMP and divalent cations. In the presence of AMP, the Zn(2+)-product and Mg(2+)-product complexes have a divalent cation present only at one of three metal binding sites (site 1). The enzyme is in the T-state conformation with a disordered loop of residues 52-72 (loop 52-72). In the absence of AMP, the enzyme crystallizes in the R-state conformation, with loop 52-72 associated with the active site. In structures without AMP, three metal-binding sites are occupied by Zn(2+) and two of three metal sites (sites 1 and 2) by Mg(2+). Evidently, the association of AMP with FBPase disorders loop 52-72, the consequence of which is the release of cations from two of three metal binding sites. In the Mg(2+) complexes (but not the Zn(2+) complexes), the 1-OH group of fructose 6-phosphate (F6P) coordinates to the metal at site 1 and is oriented for a nucleophilic attack on the bound phosphate molecule. A mechanism is presented for the forward reaction, in which Asp74 and Glu98 together generate a hydroxide anion coordinated to the Mg(2+) at site 2, which then displaces F6P. Development of negative charge on the 1-oxygen of F6P is stabilized by its coordination to the Mg(2+) at site 1.
About this Structure
1EYJ is a Single protein structure of sequence from Sus scrofa. Full crystallographic information is available from OCA.
Reference
Crystal structures of fructose 1,6-bisphosphatase: mechanism of catalysis and allosteric inhibition revealed in product complexes., Choe JY, Fromm HJ, Honzatko RB, Biochemistry. 2000 Jul 25;39(29):8565-74. PMID:10913263 Page seeded by OCA on Fri May 2 15:40:29 2008
