10.1371/journal.ppat.1000460.g007 Figure 7  Design and stability of ATP-binding–deficient Rv2623 mutants.
(A) A ribbon and stick representation of the mutation sites within the ATP binding pocket of domain 1. Mg2+ is shown as a green sphere; dotted lines indicate hydrogen-bonding contacts; atoms that constitute ATP are colored cyan (carbon), red (oxygen), blue (nitrogen), and orange (phosphorus). (B) The ATP-binding capacity of mutant Rv2623 was compared to that of wild type protein following nucleotide extraction and HPLC. Data presented are derived from analysis of three independent protein preparations. ATP binding capacity is expressed as: [(the amount of ATP bound in mutant)/(the amount of ATP bound by wild type Rv2623) * 100]. (C) Thermal denaturation curves of two individual protein preparations of Rv2623WT (WT-1, WT-2) as compared to Rv2623G117A (G117A) and Rv2623D15E (D15E). The data is expressed as the negative first-derivative of the fluorescence intensity as a function of temperature.