tailieunhanh - Báo cáo khoa học: GHP, a new c-type green heme protein from Halochromatium salexigens and other proteobacteria

We have isolated a minor soluble green-colored heme protein (GHP) from the purple sulfur bacterium, Halochromatium salexigens, which contains a c-type heme. A similar protein has also been observed in the purple bacteriaAllochromatium vinosumandRhodopseudomonas cryptolactis. This protein has wavelength maxima at 355, 420, and 540 nm and remains unchanged upon addition of sodium dithionite or potassium ferricyanide, indicating either an unusually low or high redox potential, respectively. | ềFEBS Journal GHP a new c-type green heme protein from Halochromatium salexigens and other proteobacteria Gonzalez Van Driessche1 Bart Devreese1 John C. Fitch2 Terrance E. Meyer2 Michael A. Cusanovich2 and Jozef J. Van Beeumen1 1 Department of Biochemistry Microbiology and Physiology Laboratory for Protein Biochemistry and Protein Engineering Ghent University Belgium 2 Department of Biochemistry and Molecular Biophysics University of Arizona Tucson AZ USA Keywords cysteic acid cytochrome c green heme protein Halochromatium salexigens mass spectrometry Correspondence J. Van Beeumen Universiteit Gent Vakgroep Biochemie Fysiologie en Microbiologie Laboratorium voor Eiwitbiochemie en Eiwitengineering Ledeganckstraat 35 B-9000 Gent Belgium Tel 32 9264 5109 Fax 32 9264 5338 E-mail Database The protein sequence data reported in this paper willappear in the UniProt Knowledgebase under the accession number P84848 Received 21 February 2006 revised 14 April2006 accepted 27 April 2006 doi We have isolated a minor soluble green-colored heme protein GHP from the purple sulfur bacterium Halochromatium salexigens which contains a c-type heme. A similar protein has also been observed in the purple bacteria Allochromatium vinosum and Rhodopseudomonas cryptolactis. This protein has wavelength maxima at 355 420 and 540 nm and remains unchanged upon addition of sodium dithionite or potassium ferricyanide indicating either an unusually low or high redox potential respectively. The amino-acid sequence indicates one heme per peptide chain of 72 residues and reveals weak similarity to the class I cytochromes. The usual sixth heme ligand methionine in these proteins appears to be replaced by a cysteine in GHP. Only one known cytochrome has a cysteine sixth ligand SoxA cytochrome c-551 from thiosulfate-oxidizing bacteria which is low-spin and has a high redox potential because of an un-ionized ligand. The native size of GHP is 34 kDa