2D 1H NMR studies of oxidized 2(Fe 4S 4) ferredoxin from Clostridium pasteurianum

Abstract

Oxidized ferredoxin from Clostridium pastetirianum, containing two Fe 4S 4 clusters, has been investigated using 2D 1H NMR spectroscopy at 600 MHz. 2D NMR experiments allowed complete assignment of the sixteen isotropically shifted signals corresponding to the β-CH 2 protons of the eight metal coordinated cysteines. Geminal connectivities of Cys β-CH 2 protons were identified through magnitude COSY experiments and confirmed through 2D NOESY experiments. A few additional signals could be assigned to the corresponding α-CH protons. The importance of 2D experiments to achieve firm assignments of isotropically shifted signals in paramagnetic metalloproteins is stressed.