Enzymatic Activity Analysis and Catalytic Essential Residues Identification of Brucella abortus Malate Dehydrogenase
Figure 2
Expression and purification of B. abortus MDH and the six mutant forms were identified with SDS-PAGE followed by Coomassie blue staining. (a) SDS-PAGE profiles of the expressed recombinant proteins. Lane M: prestained protein marker (SM0671, Fermentas); lane NC: total cellular proteins of E. coli BL21 transformed with pET-28a. No band of 38 kDa His-MDH was shown. Lane 1: total cellular proteins of E. coli BL21 transformed with expression plasmids pET-28a-MDH. Lanes 2–7: total cellular proteins of E. coli BL21 transformed with pET-28a-derived plasmids containing the mutant forms of the mdh gene, including Arg 89 to Leu mutant, Asp 149 to Val mutant, Arg 152 to Leu mutant, His 176 to Pro mutant, Asp178 to Val mutant, and Thr 231 to Val mutant, respectively. (b) Coomassie blue staining of the expressed recombinant proteins. Lane M: prestained protein marker (SM0671, Fermentas). Lane 1: purified proteins of MDH. Lanes 2–7: purified proteins of mutant forms MDH, including Arg 89 to Leu mutant, Asp 149 to Val mutant, Arg 152 to Leu mutant, His 176 to Pro mutant, Asp178 to Val mutant, and Thr 231 to Val mutant, respectively.
