1vyd: Difference between revisions
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==Overview== | ==Overview== | ||
All class I c-type cytochromes studied to date undergo a dynamic process, in the oxidized state, which results in the transient breaking of the, iron-methionine-sulfur bond and sufficient movement to allow the binding, of exogenous ligands (imidazole in this work). In the case of Rhodobacter, capsulatus cytochrome c(2), the sixth heme ligand Met96 and up to 14, flanking residues (positions 88-100, termed the hinge region), located, between two relatively rigid helical regions, may be involved in, structural changes leading to a transient high-spin species able to bind, ligands. We have examined 14 mutations at 9 positions in the hinge region, of Rhodobacter capsulatus cytochrome c(2) and have determined the, structure of the G95E mutant. Mutations near the N- and C-terminus of the, hinge ... | All class I c-type cytochromes studied to date undergo a dynamic process, in the oxidized state, which results in the transient breaking of the, iron-methionine-sulfur bond and sufficient movement to allow the binding, of exogenous ligands (imidazole in this work). In the case of Rhodobacter, capsulatus cytochrome c(2), the sixth heme ligand Met96 and up to 14, flanking residues (positions 88-100, termed the hinge region), located, between two relatively rigid helical regions, may be involved in, structural changes leading to a transient high-spin species able to bind, ligands. We have examined 14 mutations at 9 positions in the hinge region, of Rhodobacter capsulatus cytochrome c(2) and have determined the, structure of the G95E mutant. Mutations near the N- and C-terminus of the, hinge region do not affect the kinetics of movement but allow us to, further define that portion of the hinge that moves away from the heme to, the 93-100 region in the amino acid sequence. Mutations at positions 93, and 95 can alter the rate constant for hinge movement (up to 20-fold), presumably as a result of altering the structure of the native cytochrome, to favor a more open conformation. The structure of one of these mutants, G95E, suggests that interactions within the hinge region are stabilized, while interaction between the hinge and the heme are destabilized. In, contrast, mutations at positions 98 and 99 alter imidazole binding, kinetics but not the hinge movement. Thus, it appears that these mutations, affect the structure of the cytochrome after the hinge region has moved, away from the heme, resulting in increased solvent access to the bound, imidazole or alter interactions between the protein and the bound, imidazole. | ||
==About this Structure== | ==About this Structure== | ||
1VYD is a | 1VYD is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rhodobacter_capsulatus Rhodobacter capsulatus] with HEM as [http://en.wikipedia.org/wiki/ligand ligand]. Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1VYD OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: redox]] | [[Category: redox]] | ||
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 12:24:47 2007'' | ||
Revision as of 13:19, 5 November 2007
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CRYSTAL STRUCTURE OF CYTOCHROME C2 MUTANT G95E
OverviewOverview
All class I c-type cytochromes studied to date undergo a dynamic process, in the oxidized state, which results in the transient breaking of the, iron-methionine-sulfur bond and sufficient movement to allow the binding, of exogenous ligands (imidazole in this work). In the case of Rhodobacter, capsulatus cytochrome c(2), the sixth heme ligand Met96 and up to 14, flanking residues (positions 88-100, termed the hinge region), located, between two relatively rigid helical regions, may be involved in, structural changes leading to a transient high-spin species able to bind, ligands. We have examined 14 mutations at 9 positions in the hinge region, of Rhodobacter capsulatus cytochrome c(2) and have determined the, structure of the G95E mutant. Mutations near the N- and C-terminus of the, hinge region do not affect the kinetics of movement but allow us to, further define that portion of the hinge that moves away from the heme to, the 93-100 region in the amino acid sequence. Mutations at positions 93, and 95 can alter the rate constant for hinge movement (up to 20-fold), presumably as a result of altering the structure of the native cytochrome, to favor a more open conformation. The structure of one of these mutants, G95E, suggests that interactions within the hinge region are stabilized, while interaction between the hinge and the heme are destabilized. In, contrast, mutations at positions 98 and 99 alter imidazole binding, kinetics but not the hinge movement. Thus, it appears that these mutations, affect the structure of the cytochrome after the hinge region has moved, away from the heme, resulting in increased solvent access to the bound, imidazole or alter interactions between the protein and the bound, imidazole.
About this StructureAbout this Structure
1VYD is a Single protein structure of sequence from Rhodobacter capsulatus with HEM as ligand. Structure known Active Site: AC1. Full crystallographic information is available from OCA.
ReferenceReference
Protein dynamics in the region of the sixth ligand methionine revealed by studies of imidazole binding to Rhodobacter capsulatus cytochrome c2 hinge mutants., Dumortier C, Fitch J, Van Petegem F, Vermeulen W, Meyer TE, Van Beeumen JJ, Cusanovich MA, Biochemistry. 2004 Jun 22;43(24):7717-24. PMID:15196014
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