FIG. 1.

Residues changed in B. megaterium GPR. The amino acid sequence of B. megaterium P₄₆ is shown, with every tenth position indicated by a dot below the corresponding amino acid given in the single-letter code. Altered amino acid positions are represented by large, bold letters, and the catalytically essential aspartic acid residues (D127 and D193) are highlighted and boxed in red. The putative inhibitory loop (residues 213 to 227) is surrounded by apposed arrows, and K223 is highlighted and boxed in blue. Arrow a indicates the peptide bond cleaved in the conversion of P₄₆ to P₄₁, and arrow b indicates the peptide bond cleaved when P₄₁ undergoes a further autoprocessing reaction cleaving P₄₁ to P₃₉, which is still active against SASP. The underlined amino acids comprise GPR's autoprocessing recognition sequence. Arrow c indicates the site of trypsin cleavage that removes the C-terminal one-third of the protein while not affecting P₄₁'s activity against SASP.