Site of cleavage of pro-MTG by SAM-P45, and schematic representation of the prepro-SAM-P45 gene expression construct. (A) The amino acid sequence of MTG is boxed, and the site of cleavage of pro-MTG by SAM-P45 is indicatedby an arrow. (B) Boxes represent the coding region of the gene. Transcription of this fusion gene is controlled by the cspB promoter. CspA signal(25aa), signal sequence of CspA derived from C. ammoniagenes; N-pro(172aa), N-terminal pro-domain of SAM-P45 derived from S. albogriseolus; SAM-P45(419aa), mature domain of SAM-P45 derived from S. albogriseolus; C-pro(494aa), C-terminal pro-domain of SAM-P45 derived from S. albogriseolus.