2CZS

Crystal Structure Analysis of the Diheme c-type Cytochrome DHC2

Summary for 2CZS

• Entry DOI: 10.2210/pdb2czs/pdb
• Descriptor: cytochrome c, putative, SULFATE ION, SODIUM ION, ... (5 entities in total)
• Functional Keywords: diheme, c-type cytochrome, electron transport
• Biological source: Geobacter sulfurreducens
• Total number of polymer chains: 2
• Total formula weight: 21395.58

Authors

Heitmann, D.,Einsle, O. (deposition date: 2005-07-15, release date: 2005-10-18, Last modification date: 2024-10-23)

Primary citation

Heitmann, D.,Einsle, O.
Structural and Biochemical Characterization of DHC2, a Novel Diheme Cytochrome c from Geobacter sulfurreducens
Biochemistry, 44:12411-12419, 2005

PubMed Abstract: Multiheme cytochromes c constitute a widespread class of proteins with essential functions in electron transfer and enzymatic catalysis. Their functional properties are in part determined by the relative arrangement of multiple heme cofactors, which in many cases have been found to pack in conserved interaction motifs. Understanding the significance of these motifs is crucial for the elucidation of the highly optimized properties of multiheme cytochromes c, but their spectroscopic investigation is often hindered by the large number and efficient coupling of the individual centers and the limited availability of recombinant protein material. We have identified a diheme cytochrome c, DHC2, from the metal-reducing soil bacterium Geobacter sulfurreducens and determined its crystal structure by the method of multiple-wavelength anomalous dispersion (MAD). The two heme groups of DHC2 pack into one of the typical heme interaction motifs observed in larger multiheme cytochromes, but because of the absence of further, interfering cofactors, the properties of this heme packing motif can be conveniently studied in detail. Spectroscopic properties (UV-vis and EPR) of the protein are typical for cytochromes containing low-spin Fe(III) centers with bis-histidinyl coordination. Midpoint potentials for the two heme groups have been determined to be -135 and -289 mV by potentiometric redox titrations. DHC2 has been produced by recombinant expression in Escherichia coli using the accessory plasmid pEC86 and is therefore accessible for systematic mutational studies in further investigating the properties of heme packing interactions in cytochromes c.

PubMed: 16156654
DOI: 10.1021/bi0509999

Experimental method

X-RAY DIFFRACTION (1.5 Å)