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| - | [[Image:1ykj.gif|left|200px]] | + | {{Seed}} |
| | + | [[Image:1ykj.png|left|200px]] |
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| | {{STRUCTURE_1ykj| PDB=1ykj | SCENE= }} | | {{STRUCTURE_1ykj| PDB=1ykj | SCENE= }} |
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| - | '''A45G p-hydroxybenzoate hydroxylase with p-hydroxybenzoate bound'''
| + | ===A45G p-hydroxybenzoate hydroxylase with p-hydroxybenzoate bound=== |
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| - | ==Overview==
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| - | p-Hydroxybenzoate hydroxylase (PHBH) is a homodimeric flavoprotein monooxygenase that catalyzes the hydroxylation of p-hydroxybenzoate to form 3,4-dihydroxybenzoate. Controlled catalysis is achieved by movement of the flavin and protein between three conformations, in, out, and open [Entsch, B., et al. (2005) Arch. Biochem. Biophys. 433, 297-311]. The open conformation is important for substrate binding and product release, the in conformation for reaction with oxygen and hydroxylation, and the out conformation for the reduction of FAD by NADPH. The open conformation is similar to the structure of Arg220Gln-PHBH in which the backbone peptide loop of residues 43-46, located on the si side of the flavin, is rotated. In this paper, we examine the structure and properties of the Ala45Gly-PHBH mutant enzyme. The crystal structure of the Ala45Gly enzyme is an asymmetric dimer, with one monomer similar (but not identical) to wild-type PHBH, while the other monomer has His72 flipped into solvent and replaced with Glu73 as one of several changes in the structure. The two structures correlate with evidence from kinetic studies for two forms of Ala45Gly-PHBH. One form of the enzyme dominates turnover and hydroxylates, while the other contributes little to turnover and fails to hydroxylate. Ala45Gly-PHBH favors the in conformation over alternative conformations. The effect of this mutation on the structure and function of PHBH illustrates the importance of the si side loop in the conformational state of PHBH and, consequently, the function of the enzyme. This work demonstrates some general principles of how enzymes use conformational movements to allow both access and egress of substrates and product, while restricting access to the solvent at a critical stage in catalysis.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_15924424}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 15924424 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_15924424}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Conformation]] | | [[Category: Conformation]] |
| | [[Category: Phbh]] | | [[Category: Phbh]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 16:26:14 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 08:58:38 2008'' |
Revision as of 05:58, 29 July 2008
Template:STRUCTURE 1ykj
A45G p-hydroxybenzoate hydroxylase with p-hydroxybenzoate bound
Template:ABSTRACT PUBMED 15924424
About this Structure
1YKJ is a Single protein structure of sequence from Pseudomonas aeruginosa. Full crystallographic information is available from OCA.
Reference
Removal of a methyl group causes global changes in p-hydroxybenzoate hydroxylase., Cole LJ, Gatti DL, Entsch B, Ballou DP, Biochemistry. 2005 Jun 7;44(22):8047-58. PMID:15924424
Page seeded by OCA on Tue Jul 29 08:58:38 2008
