1w7o: Difference between revisions

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.

1W7O is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Desulfomicrobium_baculatum Desulfomicrobium baculatum] with HEC 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=1W7O OCA].  

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