1l9t
From Proteopedia
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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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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:[http://www.ncbi.nlm.nih.gov/pubmed/12538888 12538888] | 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:[http://www.ncbi.nlm.nih.gov/pubmed/12538888 12538888] | ||
[[Category: Alcaligenes faecalis]] | [[Category: Alcaligenes faecalis]] | ||
| - | [[Category: Nitrite reductase (NO-forming)]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Boulanger, M J.]] | [[Category: Boulanger, M J.]] | ||
[[Category: Murphy, M E.P.]] | [[Category: Murphy, M E.P.]] | ||
| - | [[Category: | + | [[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 | + | |
Revision as of 20:42, 2 May 2008
CRYSTAL STRUCTURE OF THE I257V VARIANT OF THE COPPER-CONTAINING NITRITE REDUCTASE FROM ALCALIGENES FAECALIS S-6
Overview
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].)
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 Fri May 2 23:42:20 2008
