Effect of HupH on the accumulation of HupS. Cell extracts from microaerobically grown (0.8% oxygen) cultures of R. leguminosarum UPM1155 transconjugant strains were subjected to Western immunoblotting analysis after PAGE separation. Samples of cell extracts containing 30 μg of total proteins were applied to each lane. HupS (A and B1), HupL (B2), and HypB (B3) proteins were detected by using the corresponding antisera. Arrows on the left side of panels indicate the position of the unprocessed (pre) and the mature (mat) forms of the structural hydrogenase proteins; the presence of an unspecific band resulting from cross-reactivity with HupS-antiserum is indicated by an asterisk. (A) Analysis of mutants. Lanes: 1, UPM1155(pALPF6) (ΔhupG); 2, UPM1155(pALPF7) (ΔhupH); 3, UPM1155(pALPF8) (ΔhupI); 4, UPM1155(pALPF9) (ΔhupJ); 5, UPM1155(pALPF4) (ΔhupD). (B1 to B3) Complementation analysis of mutants. Lanes: 1, UPM1155(pALPF1); 2, UPM1155(pALPF15) (ΔhupS); 3, UPM1155(pALPF7) (ΔhupH); 4, UPM1155(pALPF7/pPM164) (ΔhupH/hupG); 5, UPM1155(pALPF7/pPM165) (ΔhupH/hupK); 6, UPM1155(pALPF7/pPM166) (ΔhupH/hupGHI); 7, UPM1155(pALPF4) (ΔhupD).