1W7O

cytochrome c3 from Desulfomicrobium baculatus

Summary for 1W7O

• Entry DOI: 10.2210/pdb1w7o/pdb
• Descriptor: CYTOCHROME C3, HEME C (3 entities in total)
• Functional Keywords: electron transport, electron transfer, redox-bohr effect
• Biological source: DESULFOMICROBIUM BACULATUS
• Total number of polymer chains: 1
• Total formula weight: 15096.37

Authors

Coelho, A.V.,Frazao, C.,Matias, P.M.,Carrondo, M.A. (deposition date: 2004-09-07, release date: 2004-09-29, Last modification date: 2024-11-06)

Primary citation

Correia, I.,Paquete, C.,Coelho, A.V.,Almeida, C.,Catarino, T.,Louro, R.,Frazao, C.,Saraiva, L.,Carrondo, M.A.,Turner, D.,Xavier, A.
Proton-Assisted Two-Electron Transfer in Natural Variants of Tetraheme Cytochromes from Desulfomicrobium Sp
J.Biol.Chem., 279:52227-, 2004

PubMed Abstract: The tetraheme cytochrome c3 isolated from Desulfomicrobium baculatum (DSM 1743)(Dsmb) was cloned, and the sequence analysis showed that this cytochrome differs in just three amino acid residues from the cytochrome c3 isolated from Desulfomicrobium norvegicum (Dsmn): (DsmnXXDsmb) Thr-37 --> Ser, Val-45 --> Ala, and Phe-88 --> Tyr. X-ray crystallography was used to determine the structure of cytochrome c3 from Dsmb, showing that it is very similar to the published structure of cytochrome c3 from Dsmn. A detailed thermodynamic and kinetic characterization of these two tetraheme cytochromes c3 was performed by using NMR and visible spectroscopy. The results obtained show that the network of cooperativities between the redox and protonic centers is consistent with a synergetic process to stimulate the hydrogen uptake activity of hydrogenase. This is achieved by increasing the affinity of the cytochrome for protons through binding electrons and, reciprocally, by favoring a concerted two-electron transfer assisted by the binding of proton(s). The data were analyzed within the framework of the differences in the primary and tertiary structures of the two proteins, showing that residue 88, close to heme I, is the main cause for the differences in the microscopic thermodynamic parameters obtained for these two cytochromes c3. This comparison reveals how replacement of a single amino acid can tune the functional properties of energy-transducing proteins, so that they can be optimized to suit the bioenergetic constraints of specific habitats.

PubMed: 15456779
DOI: 10.1074/JBC.M408763200

Experimental method

X-RAY DIFFRACTION (1.81 Å)