1HRO

MOLECULAR STRUCTURE OF A HIGH POTENTIAL CYTOCHROME C2 ISOLATED FROM RHODOPILA GLOBIFORMIS

Summary for 1HRO

• Entry DOI: 10.2210/pdb1hro/pdb
• Descriptor: CYTOCHROME C2, PROTOPORPHYRIN IX CONTAINING FE (3 entities in total)
• Functional Keywords: electron transport, photosynthesis, heme
• Biological source: Rhodopila globiformis
• Total number of polymer chains: 2
• Total formula weight: 24291.29

Authors

Benning, M.M.,Meyer, T.E.,Holden, H.M. (deposition date: 1996-07-10, release date: 1997-01-11, Last modification date: 2024-06-05)

Primary citation

Benning, M.M.,Meyer, T.E.,Holden, H.M.
Molecular structure of a high potential cytochrome c2 isolated from Rhodopila globiformis.
Arch.Biochem.Biophys., 333:338-348, 1996

PubMed Abstract: Unlike their mitochondrial counterparts, the c-type cytochromes typically isolated from photosynthetic nonsulfur purple bacteria display a wide range of oxidation-reduction potentials. Here we describe the X-ray crystallographic analysis of the cytochrome c2 isolated from Rhodopila globiformis. This particular c-type cytochrome was selected for study because of its anomalously high redox potential of +450 mV. Crystals employed in the investigation belonged to the space group I4(1) with unit cell dimensions of a = b = 79.2 A, c = 75.2 A, and two molecules in the asymmetric unit. The structure was solved by the techniques of multiple isomorphous replacement with two heavy-atom derivatives and electron density modification procedures. Least-squares refinement of the model reduced the R-factor to 18.7% for all measured X-ray data from 30.0 to 2.2 A. The overall structural motif of the protein is composed of five alpha-helices, one type I turn, and six type II turns. As in other cytochromes c, there are two conserved water molecules located in the heme-binding pocket. Overall, the three-dimensional structure of the R. globiformis molecule is more similar to the eukaryotic c-type cytochromes than to other bacterial proteins.

PubMed: 8809072
DOI: 10.1006/abbi.1996.0400

Experimental method

X-RAY DIFFRACTION (2.2 Å)