THE ROLES OF SIGNAL PEPTIDE AND MATURE PROTEIN IN RNASE (BARNASE) EXPORT FROM BACILLUS-SUBTILIS

Barnase, an extracellular RNAse from Bacillus amyloliquefaciens is sec reted post-translationally from B. subtilis. The rate of secretion of barnase from B. subtilis was improved by replacement of the barnase si gnal peptide with a heterologous signal peptide. However, the barnase signal peptide exported Escherichia coli alkaline phosphatase faster t han mature barnase. Heat shock of B. subtilis cells did not significan tly alter the export of barnase using the barnase signal peptide. The slow rate of export of barnase from B. subtilis is due to both the sig nal peptide and the mature protein sequence rather than either alone.