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Structural and functional mechanisms of Desulfovibrio vulgaris cytochrome c3 revealed by site specific mutagenesis

Structural and functional mechanisms of Desulfovibrio vulgaris cytochrome c3 revealed by site specific mutagenesis
Structural and functional mechanisms of Desulfovibrio vulgaris cytochrome c3 revealed by site specific mutagenesis
The structural basis for the redox properties of the tetrahaem Desulfovibrio vulgaris cytochrome c3, has been investigated by site specific mutagenesis. Thermodynamic and structural characterisation of mutated cytochromes revealed the functional role of Lys45 and Thr24 in the wild type protein. Mutation of Lys45, located in the vicinity of the propionates of haem I, by the uncharged residues Thr and Gin, allowed to conclude that Lys45 controls the pKa of such propionate groups and confirms the involvement of this residue in the redox-Bohr effect ~. More recently, the replacement of Thr24, located in the vicinity ofhaem III, by Val showed how crucial Thr24 is for the stabilisation of the oxidised form of the protein. This single mutation increases the microscopic redox potential ofhaem III by 106 mV. This mutation also destabilizes the concerted two-electron step between the intermediate oxidation stages, 1 and 3, which can occur in the wild type protein. Therefore, Thr24 is responsible for the balance of the global network of cooperativities tuned to control thermodynamically the directionality of the stepwise electron transfer 2.
0162-0134
416
Salgueiro, Carlos A.
a9805ac9-e610-42ca-bb85-ef4e288eeffb
Da Costa, Patricia N.
1af11ac4-3cd6-4659-af86-53d69b5d4cdc
Turner, David L.
6c4c1ccb-a6f2-47cf-944e-e69269198a29
Messias, Ana C.
579f4c16-92a0-4d88-b5ee-9fa9cb06ddbe
van Dongen, Walter M.A.M.
85da3918-eac4-48d6-bf01-cd22d698c015
Saraiva, M.Ligia M.
35cf01d1-9bce-41e5-96cd-65e4714a1e6d
Xavier, Antonio V.
28457543-8cb4-48d4-b66a-d6524d2b3f13
Salgueiro, Carlos A.
a9805ac9-e610-42ca-bb85-ef4e288eeffb
Da Costa, Patricia N.
1af11ac4-3cd6-4659-af86-53d69b5d4cdc
Turner, David L.
6c4c1ccb-a6f2-47cf-944e-e69269198a29
Messias, Ana C.
579f4c16-92a0-4d88-b5ee-9fa9cb06ddbe
van Dongen, Walter M.A.M.
85da3918-eac4-48d6-bf01-cd22d698c015
Saraiva, M.Ligia M.
35cf01d1-9bce-41e5-96cd-65e4714a1e6d
Xavier, Antonio V.
28457543-8cb4-48d4-b66a-d6524d2b3f13

Salgueiro, Carlos A., Da Costa, Patricia N., Turner, David L., Messias, Ana C., van Dongen, Walter M.A.M., Saraiva, M.Ligia M. and Xavier, Antonio V. (2001) Structural and functional mechanisms of Desulfovibrio vulgaris cytochrome c3 revealed by site specific mutagenesis. Journal of Inorganic Biochemistry, 86 (1), 416. (doi:10.1016/S0162-0134(01)00288-4).

Record type: Article

Abstract

The structural basis for the redox properties of the tetrahaem Desulfovibrio vulgaris cytochrome c3, has been investigated by site specific mutagenesis. Thermodynamic and structural characterisation of mutated cytochromes revealed the functional role of Lys45 and Thr24 in the wild type protein. Mutation of Lys45, located in the vicinity of the propionates of haem I, by the uncharged residues Thr and Gin, allowed to conclude that Lys45 controls the pKa of such propionate groups and confirms the involvement of this residue in the redox-Bohr effect ~. More recently, the replacement of Thr24, located in the vicinity ofhaem III, by Val showed how crucial Thr24 is for the stabilisation of the oxidised form of the protein. This single mutation increases the microscopic redox potential ofhaem III by 106 mV. This mutation also destabilizes the concerted two-electron step between the intermediate oxidation stages, 1 and 3, which can occur in the wild type protein. Therefore, Thr24 is responsible for the balance of the global network of cooperativities tuned to control thermodynamically the directionality of the stepwise electron transfer 2.

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Published date: 1 August 2001

Identifiers

Local EPrints ID: 19614
URI: http://eprints.soton.ac.uk/id/eprint/19614
ISSN: 0162-0134
PURE UUID: dba98d2a-bfe2-49ea-8317-a72808fe9c15

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Date deposited: 14 Feb 2006
Last modified: 17 Jul 2017 16:31

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Contributors

Author: Carlos A. Salgueiro
Author: Patricia N. Da Costa
Author: David L. Turner
Author: Ana C. Messias
Author: Walter M.A.M. van Dongen
Author: M.Ligia M. Saraiva
Author: Antonio V. Xavier

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