THE EFFICIENCY OF PROCESSING AND SECRETION OF THE THERMOLYSIN-LIKE NEUTRAL PROTEASE FROM BACILLUS-CEREUS DOES NOT REQUIRE THE WHOLE PROSEQUENCE, BUT DOES DEPEND ON THE NATURE OF THE AMINO-ACID-SEQUENCE IN THE REGION OF THE CLEAVAGE SITE

Using deletion mutants, It is shown that part of the prosequence, the Omega-peptide (-4, -24), of the thermolysin-like neutral protease (TNP) from Bacillus cereus, Cnp, is not required for efficient processing and secretion of fully functional mature protease. It is demonstrated that the rate and selectivity of proprotein processing is dependent on both the flexibility and primary sequence of the processing site. Processing is found to be particularly sensitive to the nature of the amino acid three residues upstream from the site of cleavage. A consensus sequence for TNP proprotein processing has been identified, which provides further insights. Finally, a larger deletion of a portion of the Cnp prosequence upstream from the Omega-peptide that includes amino acids conserved among TNPs reduces the rate of processing and secretion of Cnp and results in the accumulation of export-incompetent pre-proprotein in the cell fraction.