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| | {{STRUCTURE_1l9t| PDB=1l9t | SCENE= }} | | {{STRUCTURE_1l9t| PDB=1l9t | SCENE= }} |
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| - | '''CRYSTAL STRUCTURE OF THE I257V VARIANT OF THE COPPER-CONTAINING NITRITE REDUCTASE FROM ALCALIGENES FAECALIS S-6'''
| + | ===CRYSTAL STRUCTURE OF THE I257V VARIANT OF THE COPPER-CONTAINING NITRITE REDUCTASE FROM ALCALIGENES FAECALIS S-6=== |
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| - | ==Overview==
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| - | Unlike the heme cd(1)-based nitrite reductase enzymes, the molecular mechanism of copper-containing nitrite reductases remains controversial. A key source of controversy is the productive binding mode of nitrite in the active site. To identify and characterize the molecular determinants associated with nitrite binding, we applied a combinatorial mutagenesis approach to generate a small library of six variants at position 257 in nitrite reductase from Alcaligenes faecalis S-6. The activities of these six variants span nearly two orders of magnitude with one variant, I257V, the only observed natural substitution for Ile257, showing greater activity than the native enzyme. High-resolution (> 1.8 A) nitrite-soaked crystal structures of these variants display different modes of nitrite binding that correlate well with the altered activities. These studies identify for the first time that the highly conserved Ile257 in the native enzyme is a key molecular determinant in directing a catalytically competent mode of nitrite binding in the active site. The O-coordinate bidentate binding mode of nitrite observed in native and mutant forms with high activity supports a catalytic model distinct from the heme cd(1) NiRs. (The atomic coordinates for I257V[NO(2)(-)], I257L[NO(2)(-)], I257A[NO(2)(-)], I257T[NO(2)(-)], I257M[NO(2)(-)] and I257G[NO(2)(-)] AfNiR have been deposited in the Protein Data Bank [PDB identification codes are listed in Table 2].)
| + | The line below this paragraph, {{ABSTRACT_PUBMED_12538888}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 12538888 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_12538888}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Murphy, M E.P.]] | | [[Category: Murphy, M E.P.]] |
| | [[Category: Cupredoxin fold]] | | [[Category: Cupredoxin fold]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 23:42:20 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jul 2 12:03:03 2008'' |
Revision as of 09:03, 2 July 2008
Template:STRUCTURE 1l9t
CRYSTAL STRUCTURE OF THE I257V VARIANT OF THE COPPER-CONTAINING NITRITE REDUCTASE FROM ALCALIGENES FAECALIS S-6
Template:ABSTRACT PUBMED 12538888
About this Structure
1L9T is a Single protein structure of sequence from Alcaligenes faecalis. Full crystallographic information is available from OCA.
Reference
Directing the mode of nitrite binding to a copper-containing nitrite reductase from Alcaligenes faecalis S-6: characterization of an active site isoleucine., Boulanger MJ, Murphy ME, Protein Sci. 2003 Feb;12(2):248-56. PMID:12538888
Page seeded by OCA on Wed Jul 2 12:03:03 2008
