Figure 2.

SDS/PAGE analysis of the oligomeric state of bMsrA upon treatment with Met(O). The Coomassie-stained gels show the formation of intermolecular disulfide bonds between some of the variants of bMsrA after incubation with substrate under nonreducing conditions (see Materials and Methods). The addition of DTT reduced the polymeric forms [e.g., dimer (D), trimer (TR), and tetramer (TE)] to the monomeric form (M), which migrated just below the 31-kDa molecular mass standard. Lane 1, molecular mass standards; lane 2, protein incubated in the absence of l-Met(O) and analyzed under nonreducing conditions; lane 3, protein incubated in the presence of l-Met(O) and analyzed under nonreducing conditions; lane 4, protein incubated with l-Met(O) and analyzed after treatment with DTT.