N HSQC spectra of the C15S mutant and wild-type Grx2. (A) Assigned HSQC spectrum of the C15S mutant. (B) HSQC spectra overlay of the C15S mutant (black) and wild-type Grx2 (red). Several residues of wild-type Grx2 protein are represented with prime(') marks. All assigned residues are labeled and one crowded region is magnified (insets). The mutated residue C15S is indicated by red arrow. The assigned set of cross peaks from amide side-chains of Asn and Gln residues is indicated using a gray horizontal bar. The unassigned peaks are marked by '*' and the tryptophan side chain is marked by 'sc'.