Multinuclear magnetic resonance studies of the 2Fe.2S* ferredoxin from Anabaena species strain PCC 7120. 2. Sequence-specific carbon-13 and nitrogen-15 resonance assignments of the oxidized form

Multinuclear two-dimensional NMR techniques were used to assign nearly all diamagnetic 13C and 15N resonances of the plant-type 2Fe.2S* ferredoxin from Anabaena sp. strain PCC 7120. Since a 13C spin system directed strategy had been used to identify the 1H spin systems [Oh, B.-H., Westler, W. M., & Markley, J. L. (1989) J. Am. Chem. Soc. 111, 3083-3085], the sequence-specific 1H assignments [Oh, B.-H., & Markley, J. L. (1990) Biochemistry (first paper of three in this issue)] also provided sequence-specific 13C assignments. Several resonances from 1H-13C groups were assigned independently of the 1H assignments by considering the distances between these nuclei and the paramagnetic 2Fe.2S* center. A 13C-15N correlation data set was used to assign additional carbonyl carbons and to analyze overlapping regions of the 13C-13C correlation spectrum. Sequence-specific assignments of backbone and side-chain nitrogens were based on 1H-15N and 13C-15N correlations obtained from various two-dimensional NMR experiments.