Fig. 1. Expression of vacuolar ATPase subunit B isoforms vatB1 and vatB2 in BL21(DE3)pLysS cells: bacterial lysates have been separated by SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) and stained with Coomassie blue. Expression was induced with 1 µmol l^-1 IPTG (isopropylthiogalactoside). The expression of recombinant protein was clearly induced after 2 h, and the expression increased with time (e.g. after 4 h). Arrows indicate the position of reference vatB1 and vatB2 bands at approximately 60 kDa.