Journal of Microbiology

A possible mechanism responsible for translocation and secretion an alkaliphilic bacillus sp. S-1 pullulanase: Shim, Jae Kyoung , Kim, Kyoung Sook , Kim, Cheorl Ho; J. Microbiol. 1997;35(3):213-221.

Abstract: The secretion of the alkaliphilic Bacillus sp. S-1 extracellular pullulanase involves translocation across the cytoplasmic membrane of the Gram-positive bacterial cell envelope. Translocation of the intracellular pullulanase PUL-I, was traced to elucidate the mechanism and pathway of protein secretion from an alkaliphilic Bacillus sp. S-1. Pullulanase could be slowly but quantitatively released into the medium during growth of the cells in medium containing proteinase K. The released pullulanase lacked the N-terminal domain. The N-terminus is the sole membrane anchor in the pullulanase protein and was not affected by proteases, confirming that it is not exposed on the cell surface. Processing of a 180,000M_r pullulanase to a 140,000M_r polypeptide has been demonstrated in cell extracts using antibodies raised against 140,000M_r extracellular form. Processing of the 180,000 M_r protein occured during the preparation of extracts in an alkaline pH condition. A modified rapid extraction procedure suggested that the processing event also occured in vivo. Processing apparently increased the activity of pullulanase. The western blotting analysis with mouse anti-serum against 140-kDa extracellular pullulanase PUL-E showed that PUL-I is processed into PUL-X via intermediate form of PUL-E. Possible explanationa for the translocation are discussed.

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