Figure 1

Absolute differences in the amide ¹H chemical shifts among pairs of parental and metal binding site-swapped rubredoxins. The chemical shift differences between each hybrid and each parental protein are illustrated in panels A to D. Panel E shows the corresponding differences between the parental Cp and Pf A2K rubredoxins. In this last panel, the seven nonconserved metal binding site residues are highlighted in CPK representation for each parental protein. For the bars and the protein figures inserted in each panel, as well as in the sequence alignment at the bottom, red denotes residues derived from the hyperthermophilic Pf A2K rubredoxin sequence, while blue denotes residues derived from the mesophilic Cp sequence. Sequence-conserved residues are indicated with solid black bars. The gray background indicates the sequence segments that have been interchanged so as to generate the models for the metal binding site-swapped hybrids. The mutations for the hyperthermophile protein in these segments consist of T7K, V8I, L41I, V44A, G45P, D47S and Q48E.