1M1Q

P222 oxidized structure of the tetraheme cytochrome c from Shewanella oneidensis MR1

Summary for 1M1Q

• Entry DOI: 10.2210/pdb1m1q/pdb
• Related: 1M1P 1M1R
• Descriptor: small tetraheme cytochrome c, SULFATE ION, HEME C, ... (4 entities in total)
• Functional Keywords: atomic structure of oxidized tetraheme cytochrome c, electron transport
• Biological source: Shewanella oneidensis MR-1
• Total number of polymer chains: 1
• Total formula weight: 12339.76

Authors

Leys, D.,Meyer, T.E.,Tsapin, A.I.,Nealson, K.H.,Cusanovich, M.A.,Van Beeumen, J.J. (deposition date: 2002-06-20, release date: 2002-08-14, Last modification date: 2024-12-25)

Primary citation

Leys, D.,Meyer, T.E.,Tsapin, A.I.,Nealson, K.H.,Cusanovich, M.A.,Van Beeumen, J.J.
Crystal structures at atomic resolution reveal the novel concept of 'electron-harvesting' as a role for the small tetraheme cytochrome c
J.Biol.Chem., 277:35703-35711, 2002

PubMed Abstract: The genus Shewanella produces a unique small tetraheme cytochrome c that is implicated in the iron oxide respiration pathway. It is similar in heme content and redox potential to the well known cytochromes c(3) but related in structure to the cytochrome c domain of soluble fumarate reductases from Shewanella sp. We report the crystal structure of the small tetraheme cytochrome c from Shewanella oneidensis MR-1 in two crystal forms and two redox states. The overall fold and heme core are surprisingly different from the soluble fumarate reductase structures. The high resolution obtained for an oxidized orthorhombic crystal (0.97 A) revealed several flexible regions. Comparison of the six monomers in the oxidized monoclinic space group (1.55 A) indicates flexibility in the C-terminal region containing heme IV. The reduced orthorhombic crystal structure (1.02 A) revealed subtle differences in the position of several residues, resulting in decreased solvent accessibility of hemes and the withdrawal of a positive charge from the molecular surface. The packing between monomers indicates that intermolecular electron transfer between any heme pair is possible. This suggests there is no unique site of electron transfer on the surface of the protein and that electron transfer partners may interact with any of the hemes, a process termed "electron-harvesting." This optimizes the efficiency of intermolecular electron transfer by maximizing chances of productive collision with redox partners.

PubMed: 12080059
DOI: 10.1074/jbc.M203866200

Experimental method

X-RAY DIFFRACTION (0.97 Å)