1LM2

NMR structural characterization of the reduction of chromium(VI) to chromium(III) by cytochrome c7

Summary for 1LM2

• Entry DOI: 10.2210/pdb1lm2/pdb
• Related: 1EHJ 1HH5 1new 2new
• NMR Information: BMRB: 4743
• Descriptor: cytochrome c7, CHROMIUM ION, HEME C (3 entities in total)
• Functional Keywords: chromium, cytochrome c7, electron transport
• Biological source: Desulfuromonas acetoxidans
• Total number of polymer chains: 1
• Total formula weight: 9187.81

Authors

Assfalg, M.,Bertini, I.,Bruschi, M.,Michel, C.,Turano, P. (deposition date: 2002-04-30, release date: 2002-07-31, Last modification date: 2024-10-30)

Primary citation

Assfalg, M.,Bertini, I.,Bruschi, M.,Michel, C.,Turano, P.
The metal reductase activity of some multiheme cytochromes c: NMR structural characterization of the reduction of chromium(VI) to chromium(III) by cytochrome c(7).
Proc.Natl.Acad.Sci.USA, 99:9750-9754, 2002

PubMed Abstract: The redox reaction between CrO(4)(2-) and the fully reduced three-heme cytochrome c(7) from Desulfuromonas acetoxidans to give chromium(III) and the fully oxidized protein has been followed by NMR spectroscopy. The hyperfine coupling between the oxidized protein protons and chromium(III), which remains bound to the protein, gives rise to line-broadening effects on the NMR resonances that can be transformed into proton-metal distance restraints. Structure calculations based on these unconventional constraints allowed us to demonstrate that chromium(III) binds at a unique site and to locate it on the protein surface. The metal ion is located 7.9 +/- 0.4 A from the iron of heme IV, 16.3 +/- 0.7 A from the iron of heme III, and 22.5 +/- 0.5 A from the iron of heme I. Shift changes caused by the presence of unreactive MoO(4)(2-), a CrO(4)(2-) analogue, indicate the involvement of the same protein area in the anion binding. The titration of the oxidation of cytochrome c(7) shows a detailed mechanism of action. The presence of a specific binding site supports the hypothesis of the biological role of this cytochrome as a metal reductase.

PubMed: 12119407
DOI: 10.1073/pnas.152290999

Experimental method

SOLUTION NMR