title: The structure of bacilysin and other products of Bacillus subtilis.
abstract: 1. Mass spectra of the trimethylsilyl derivative and the methyl ester of the N-trifluoroacetyl derivative of bacilysin indicated that the antibiotic had a molecular weight of 270. Several peaks in the spectrum of the methyl ester were consistent with the presence of an N-terminal alanine residue in the molecule. 2. The proton-magnetic-resonance spectrum of bacilysin confirmed that the antibiotic contained an epoxide group and the spin-spin splitting of the protons of the epoxide group indicated that the side chain of the epoxycyclohexanone ring was attached at C-4 and was alphabeta to the keto group. 3. The formation of an alphabeta-unsaturated ketone on reduction of bacilysin with chromous chloride also showed that the epoxide was alphabeta to the keto group. 4. The optical-rotatory-dispersion curve of bacilysin showed a positive Cotton effect. On the assumption that the reversed Octant rule for alphabeta-epoxyketones was applicable this revealed the absolute stereochemistry and enabled a definitive structure to be assigned to the molecule. 5. Similar measurements showed that substance AA1, isolated from culture supernatants, was the C-terminal amino acid of bacilysin. 6. Hydrolysis of substance P2 with leucine aminopeptidase and the mass spectrum of the methyl ester of its N-trifluoroacetyl derivative showed that this substance was l-analyl-l-alanine. 7. These results are discussed in relation to the biogenesis of bacilysin.
mesh_terms: D000409:Alanine / Q000032:analysis; D000596:Amino Acids / Q000032:analysis; D000900:Anti-Bacterial Agents / Q000032:analysis* / Q000096:biosynthesis; D001412:Bacillus subtilis / Q000378:metabolism*; D002857:Chromium; D003510:Cyclohexanes; D004151:Dipeptides / Q000032:analysis; D004952:Esters; D004988:Ethers, Cyclic / Q000032:analysis; D005463:Fluoroacetates; D007659:Ketones; D007931:Leucyl Aminopeptidase; D009682:Magnetic Resonance Spectroscopy; D008970:Molecular Weight; D009905:Optical Rotatory Dispersion; D011522:Protons; D013057:Spectrum Analysis
chemical_list: D000596:Amino Acids; D000900:Anti-Bacterial Agents; D003510:Cyclohexanes; D004151:Dipeptides; D004952:Esters; D004988:Ethers, Cyclic; D005463:Fluoroacetates; D007659:Ketones; D011522:Protons; D002857:Chromium; D007931:Leucyl Aminopeptidase; D000409:Alanine