I. Bertini et al., AN NMR-STUDY OF THE 7FE-8S FERREDOXIN FROM RHODOPSEUDOMONAS-PALUSTRISAND REINTERPRETATION OF DATA ON SIMILAR SYSTEMS, Biochemistry, 36(12), 1997, pp. 3570-3579
The oxidized 7Fe-8S ferredoxin from Rhodopseudomonas palustris is show
n to possess a unique H-1 NMR spectrum displaying at least one hyperfi
ne-shifted beta-CH2 signal for each cysteine bound to the [3Fe-4S] clu
ster. COSY and TOCSY spectra and 1- and 2-dimensional NOE experiments,
in conjunction with a thorough reexamination of the H-1 NMR data on s
imilar systems, permitted the sequential assignment of all of the cyst
eine beta-CH2 protons even in the absence of the amino acid sequence.
The sequential assignment stems on the homology of the hyperfine shift
pattern with those of other sequenced 7Fe-8S ferredoxins, which point
s to a substantial homology in tertiary structure. From the assignment
, an analysis of the antiferromagnetic coupling in the [3Fe-4S] system
was performed on the basis of a general model of exchange coupling. T
he NMR signal patterns of [3Fe-4S] clusters in both 3Fe-4S and 7Fe-8S
ferredoxins have been discussed, and some correlations are proposed be
tween signal patterns and the primary sequence.