IDENTIFICATION OF A REGION OF INTERACTION BETWEEN ESCHERICHIA-COLI SECA AND SECY PROTEINS

SecA ATPase promotes Escherichia coli protein translocation by its ass ociation with the preprotein or preprotein-SecB complex, anionic phosp holipids, and the other core component of translocase, integral membra ne protein SecYEG, Using ligand affinity blotting we demonstrate a dir ect interaction of SecA with SecY protein, Proteolysis and gene trunca tion or fusion studies were used to further define this interaction. O ur results demonstrate that the carboxyl-terminal third of SecA protei n binds to the amino-terminal 107 amino acid residues of SecY protein, The direct demonstration of these interactions culminate studies that have inferred an interaction between SecA and SecYEG, and they are co nsistent with studies suggesting that this region of SecA interacts wi th the inner membrane.