Resumen de Influence of a "Streptomyces lividans" SecG functional analogue on protein secretion

Carmen Palomino, Rafael P. Mellado

• The membrane protein complex translocase mediates the translocation of bacterial proteins. In this complex, the SecY, SecE, and SecG proteins constitute an integral membrane domain. Sequence comparison revealed a potential secGlike gene in the gram-positive soil bacterium Streptomyces lividans. Chromosomal deletion of this gene resulted in a sporulation defect and an overall deficiency in secretion. The SecG-depleted strain was able to overproduce and secrete á-amylase, but the appearance of the oversynthesized protein outside the cell was delayed compared to the protein produced by the wildtype strain. SecG deficiency was found to result in more pronounced effects in S. lividans than in Bacillus subtilis or Escherichia coli.