New Findings on Cephalosporin C Biosynthesis

Fujisawa, Yukio; Shirafugi, H; Kida, Makoto; Nara, Kiyoshi; Yoneda, Masahiko; Kanzaki, Toshihiko

doi:10.1038/newbio246154a0

Cited by 42 publications

(16 citation statements)

References 13 publications

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“…An acetyltransferase converting deacetylcephalosporin C to cephalosporin C has been previously demonstrated (3) deacetylcephalosporin C would account for the increased deacetoxycephalosporin C and decrease in deacetylcephalosporin C accumulation if the affinity of the acetyltransferase for its substrate was sufficiently low. Hypothetically, a hydroxylase converts deacetoxycephalosporin C to deacetylcephalosporin C. If the genes coding for the acetyl-transferase and the proposed hydroxylase were part of the same operon and were adjacent, a polar mutation in the acetyltransferase gene could also account for the increased deacetoxycephalosporin C and decreased deacetylcephalosporin C accumulation observed for MH63.…”

Section: Discussionmentioning

confidence: 99%

Synthesis of Deactoxycephalosporin C by a Mutant of Cephalosporium acremonium

Queener

Capone

Radue

et al. 1974

Antimicrob Agents Chemother

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A number of Cephalosporium acremonium mutants blocked in the synthesis of cephalosporin C were investigated for accumulation of other ,3-lactam compounds. The non-cephalosporin C producers were isolated after exposing the superior cephalosporin C-producing strain M8650-4 to ultraviolet light (268 nm). One of the blocked mutants, MH63, accumulated deacetylcephalosporin C (0.4 mg/ml), deacetoxycephalosporin C (1.5 mg/ml), and penicillin N (2.7 mg/ml). In contrast, the parent of MH63 produced high levels of cephalosporin C as well as deacetylcephalosporin C (2.2 mg/nal) and penicillin N (1.0 mg/ml), but only traces of deacetoxycephalosporin C (about 0.1 mg/ml). Deacetoxycephalosporin C was isolated from the mutant strain and identified by ultraviolet light, nuclear magnetic resonance, bioactivity spectrum, and co-migration with authentic standard in three chromatography systems.

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Section: Discussionmentioning

confidence: 99%

Synthesis of Deactoxycephalosporin C by a Mutant of Cephalosporium acremonium

Queener

Capone

Radue

et al. 1974

Antimicrob Agents Chemother

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“…Acremonium chrysogenum (syn. Cephalosporium acremonium) mutants that are impaired in cephalosporin C biosynthesis and accumulate DAC were reported several years ago [3,4]. Cell-free extracts of these mutants are unable to convert DAC into cephalosporin C, which is at variance with what occurs with the wild type [5].…”

Section: Introductionmentioning

confidence: 99%

Molecular characterization of the Acremonium chrysogenum cefG gene product: the native deacetylcephalosporin C acetyltransferase is not processed into subunits

Velasco

Gutiérrez

Campoy

et al. 1999

Biochemical Journal

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Constructions starting at each of the three in-frame ATG codons of the Acremonium chrysogenum cefG gene (Met1, Met46 and Met60) were expressed in Escherichia coli, obtaining proteins of 49, 44 and 43 kDa, respectively. All three proteins showed deacetylcephalosporin C (DAC) acetyltransferase activity. The native A. chrysogenum DAC acetyltransferase was purified to electrophoretic homogeneity by immunoaffinity chromatography. It showed a molecular mass of 50 kDa by filtration in calibrated Sephadex G-75 SF or Superose 12 (FPLC) columns. The N-terminal end of the pure DAC acetyltransferase was Met-Leu-Pro-Ser-Ala-Gln-Val-Ala-Arg-Leu, which matched perfectly the deduced amino acid sequence starting at Met1. The putative α- and β-subunits of DAC acetyltransferase were also obtained in E. coli but showed no enzymic activity either separately or in combination. Immunoblotting (Western) analysis revealed that the 50 kDa DAC acetyltransferase showed high protein levels in A. chrysogenum cultures at 72 and 96 h and decreased sharply thereafter, but in all cases no detectable processing of the enzyme into subunits was found. Three different A. chrysogenum strains (including the wild-type Brotzu strain and two high-cephalosporin-producing mutants) showed the same unprocessed 50 kDa DAC acetyltransferase. The non-producer mutant ATCC 20371 showed no DAC acetyltransferase protein band but formed a normal transcript of 1.4 kb.

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“…Using this procedure and starting from L-aspartic acid a stereocontrolled synthesis leading to ( + )-thienamycin has been achieved (112). The ~-lactam precursor was formed from the protected amino-acid (142) and elaborated to the N-silylated azetidinone (145). Introduction of the hydroxyethyl substituent to form (146) was by way of a stereocontrolled potassium selectride reduction of the corresponding acetyl compound.…”

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confidence: 99%