Membrane Penicillinase of Bacillus licheniformis 749/C: Sequence and Possible Repeated Tetrapeptide Structure of the Phospholipopeptide Region

• Published in: Proceedings of the National Academy of Sciences - PNAS 1976-05, Vol.73 (5), p.1457-1461
• Main Authors: Yamamoto, Shinpei, Lampen, J. Oliver
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Amino acids; Apoproteins - analysis; Bacillus; Bacillus - enzymology; Bacillus - ultrastructure; Cell Membrane - enzymology; Cell membranes; Codons; Enzymes; Enzymology; Fatty acids; Gels; Lipoproteins - analysis; Messenger RNA; Papain; Penicillinase - analysis; Penicillinase - metabolism; Pepsin A; Phosphatidylserines; Phospholipids - analysis
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.73.5.1457

The membrane penicillinase (EC 3.5.2.6; penicillin amido-β -lactamhydrolase) of Bacillus licheniformis 749/C, which appears to be an intermediate in the formation of the exoenzyme, is a phospholipoprotein that carries an NH2-terminal chain of 24 amino acids (only serine, glycine, aspartic acid, asparagine, glutamic acid, and glutamine) and a phosphatidylserine that is not present in the exoenzyme. Trypsin cleavage of the membrane enzyme produces a 26-residue phospholipopeptide whose sequence is: phosphatidylserine-Asn-Asp-Glu-Gly-Gly-Asp-Ser-Gly-Asn-Gln-Ser-Gly-Asp- Gly-Asn-Gln-Ser-Glu- Glu-Asn- Glu-Asp- Gln-Ser-Lys-COOH. This segment could be derived from a tetrapeptide [Asp(or Asn)-Glu(or Gln)-Ser-Gly] by a series of mutations (which would require reasonable base transitions and transversions), four deletions and one insertion. The putative mRNA for the peptide chain would have a high purine content (up to 80%) and a structure resembling poly(A). The phospholipopeptide is long enough to span the lipid bilayer of the membrane. Hence, the phosphatidylserine residue could be on either face of the membrane and still allow the major catalytic portion of the enzyme to be in the external aqueous phase.