ISSN:
1573-5001
Keywords:
Cytochromec 3
;
Ferredoxin I
;
1H NMR
;
Assignment of heme signals
;
Inter-redoxsite interaction
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Summary The1H NMR signals of the heme methyl, propionate and related chemical groups of cytochromec 3 fromDesulfovibrio vulgaris Miyazaki F (D.v. MF) were site-specifically assigned by means of ID NOE, 2D DQFCOSY and 2D TOCSY spectra. They were consistent with the site-specific assignments of the hemes with the highest and second-lowest redox potentials reported by Fan et al. (Biochemistry,29 (1990) 2257–2263). The site-specific heme assignments were also supported by NOE between the methyl groups of these hemes and the side chain of Val18. All the results contradicted the heme assignments forD.v. MF cytochromec 3 made on the basis of electron spin resonance (Gayda et al. (1987)FEBS Lett.,217 57–61). Based on these assignments, the interaction of cytochromec 3 withD.v. MF ferredoxin I was investigated by NMR. The major interaction site of cytochromec 3 was identified as the heme with the highest redox potential, which is surrounded by the highest density of positive charges. The stoichiometry and association constant were two cytochromec 3 molecules per monomer of ferredoxin I and 108 M−2 (at 53 mM ionic strength and 25°C), respectively.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01875520
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