INFLUENCE OF A CELL-WALL-ASSOCIATED PROTEASE ON PRODUCTION OF ALPHA-AMYLASE BY BACILLUS-SUBTILIS

AmyL, an extracellular alpha-amylase from Bacillus licheniformis, is r esistant to extracellular proteases secreted by Bacillus subtilis duri ng growth. Nevertheless, when AmyL is produced and secreted by B. subt ilis, it is subject to considerable cell-associated proteolysis. Cell- wall-bound proteins CWBP52 and CWBP23 are the processed products of th e B, subtilis wprA gene. Although no activity has been ascribed to CWB P23, CWBP52 exhibits serine protease activity. Using a strain encoding an inducible wprA gene, we show that a product of wprA, most likely C WBP52, is involved in the posttranslocational stability of AmyL. A con struct in which wprA is not expressed exhibits an increased yield of a lpha-amylase, The potential role of wprA in protein secretion is discu ssed, together with implications for the use of B. subtilis and relate d bacteria as hosts for the secretion of heterologous proteins.