Expression of doubly labeled Saccharomyces cerevisiaeiso-1 ferricytochrome c and 1H, 13C and 15N chemical shift assignments by multidimensional NMR

Abstract

We have expressed [U- 13C, 15N]-labeled Saccharomyces cerevisiae iso-1 cytochrome c C102T;K72A in Escherichia coli with a yield of 11 mg/l of growth medium. Nuclear magnetic resonance (NMR) studies were conducted on the Fe 3+ form of the protein. We report herein chemical shift assignments for amide 1H and 15N, 13C°, 13C α, 13C β, 1H α and 1H β resonances based upon a series of three-dimensional NMR experiments: HNCA, HN(CO)CA, HNCO, HN(CA)CO, HNCACB, HCA(CO)N, HCCH-TOCSY and HBHA(CBCA)NH. An investigation of the chemical shifts of the threonine residues was also made by using density functional theory in order to help solve discrepancies between 15N chemical shift assignments reported in this study and those reported previously.