SDS-polyacrylamide gel electrophoresis and Immunoblot analysis. (A) SDS-polyacrylamide gel electrophoresis of whole-cell lysates of uninduced and induced recombinant E. coli cells. Lane 1, 4- Molecular mass marker (116 kDa, 66.2, 45, 35, 25, 18.4, 14.4, Fermentas), the molecular mass standards are indicated in kDa on left side. Lane 2, 3- Lysate of uninduced and induced E. coli (pET28a/mce1A) cells respectively. Lane 5, 6- Lysate of uninduced and induced E. coli (pET28a/mce4A) cells respectively. Mce1A and Mce4A are indicated by arrows. (B) Immunoblot of purified Mce1A and Mce4A proteins. Anti-His-tag antibody was used to demonstrate the fusion proteins. Lane1-Purified Mce1A protein (2 μg). Lane 2- Pre-stained molecular mass marker (188 kDa, 62, 49, 38, 28, 18, 14, 6, 3, Invitrogen), the molecular mass standards in kDa are indicated on left side. Lane 3-Purified Mce4A protein (2 μg). Mce1A and Mce4A are indicated by arrows.