Disease relevance of Penicillin M

• Isolation, sequence determination and expression in Escherichia coli of the isopenicillin N synthetase gene from Cephalosporium acremonium [1].
• Nucleotide sequence of the isopenicillin N synthase gene (pcbC) of the gram negative Flavobacterium sp. SC 12,154 [2].
• Preliminary experiments have shown that a similar isopenicillin N synthetase can be extracted from Streptomyces clavuligerus [3].
• The isopenicillin N synthase (pcbC) and acyl-CoA:6-APA acyltransferase (penDE) genes of Penicillium chrysogenum were located in a 19.5-kb DNA fragment that had been previously cloned in phage vector EMBL3 [4].
• Determination of the nucleotide sequence downstream from the Lysobacter lactamgenus pcbC gene encoding isopenicillin N synthase revealed that five open-reading frames (ORF) including the pcbC gene were tightly linked in the same orientation [5].

High impact information on Penicillin M

• Studies on cytochrome P450, isopenicillin N synthase, cytochrome cd1 nitrite reductase, copper amine oxidase and bacteriorhodopsin were selected as examples, and the results are discussed [6].
• The predicted amino acid sequences of isopenicillin N synthetase from both Cephalosporium acremonium and Penicillium chrysogenum have two cysteine residues in analogous positions (Cys-106 and Cys-255 in the C. acremonium numbering) [7].
• Analysis of the role of cysteine residues in isopenicillin N synthetase activity by site-directed mutagenesis [7].
• NocJ is the first member of a new class of beta-lactam aminoacyl side chain epimerases, the first two classes being the evolutionarily distinct prokaryotic PLP-dependent isopenicillin N epimerase and the fungal isopenicillin N epimerase two protein system [8].
• A novel epimerization system in fungal secondary metabolism involved in the conversion of isopenicillin N into penicillin N in Acremonium chrysogenum [9].

Chemical compound and disease context of Penicillin M

• Isopenicillin N synthase (IPNS) from Streptomyces jumonjinensis (M(r) 37,902) is a non-heme ferrous iron-containing enzyme that catalyzes the oxidative cyclization of the tripeptide delta-(L-alpha-aminoadipoyl)-L-cysteinyl-D-valine (ACV) to form isopenicillin N [10].
• Cloning and characterization of the isopenicillin N synthase gene of Streptomyces griseus NRRL 3851 and studies of expression and complementation of the cephamycin pathway in Streptomyces clavuligerus [11].
• Deacetoxycephalosporin C (DAOC), a precursor of cephalosporins excreted by Cephalosporium and Streptomyces species, has been produced in Penicillium chrysogenum transformed with DNA containing a hybrid penicillin N expandase gene (cefEh) and a hybrid isopenicillin N epimerase gene (cefDh) [12].
• The beta-lactam biosynthesis genes for isopenicillin N epimerase and deacetoxycephalosporin C synthetase are expressed from a single transcript in Streptomyces clavuligerus [13].
• Replacement of tyrosine-197 and the corresponding tyrosine-195 to isoleucine in Cephalosporium acremonium and Streptomyces clavuligerus isopenicillin N synthase [14].

Biological context of Penicillin M

• Three binding sites for the Aspergillus nidulans PacC zinc-finger transcription factor are necessary and sufficient for regulation by ambient pH of the isopenicillin N synthase gene promoter [15].
• The isopenicillin N synthase (ipnA) gene, encoding a key penicillin biosynthetic enzyme in Aspergillus nidulans, represents a prototype of an alkaline-expressed gene. ipnA is under ambient pH regulation, and its promoter (ipnAp) contains binding sites for the zinc-finger transcription factor PacC [15].
• Previous work established that pH regulation of gene expression in Aspergillus nidulans, a major determinant of penicillin biosynthesis, is mediated by the zinc-finger transcription factor PacC, an activator of transcription of the isopenicillin N synthase gene [16].
• Evolution of isopenicillin N synthase genes may have involved horizontal gene transfer [17].
• Deacetylcephalosporin C Production in Penicillium chrysogenum by Expression of the Isopenicillin N Epimerization, Ring Expansion, and Acetylation Genes [18].

Anatomical context of Penicillin M

• 2. In a cell-free system prepared by lysis of protoplasts of Cephalosporium acremonium 3H was incorporated from the doubly labelled tripeptide into a compound that behaved like penicillin N or isopenicillin N [19].
• In a cell-free system prepared by lysis of protoplasts of Cephalosporium acremonium mutant M-0198, isopenicillin N was converted into a penicillinase-resistant material that behaved like deacetoxycephalosporin C on high-pressure liquid chromatography analysis [20].
• A mutant in the carboxyl-terminal region of the isopenicillin N acyltransferase lacking the three final amino acids of the enzymes was not properly located in the microbodies and failed to synthesize penicillin in vivo [21].
• The isopenicillin N acyltransferase was shown to be located in microbodies, whereas the isopenicillin N synthase has been reported to be present in vesicles of the Golgi body and in the cell wall [21].
• High level expression in Escherichia coli of isopenicillin N synthase genes from Flavobacterium and Streptomyces, and recovery of active enzyme from inclusion bodies [22].

Associations of Penicillin M with other chemical compounds

• Crystallographic data have established a 2-His-1-carboxylate facial triad as a structural motif common to a number of mononuclear nonheme iron enzymes, including isopenicillin N synthase, tyrosine hydroxylase and naphthalene dioxygenase [23].
• Ferrous active site of isopenicillin N synthase: genetic and sequence analysis of the endogenous ligands [10].
• Isopenicillin N synthase (IPNS) from Cephalosporium acremonium (M(r) 38,400) is an iron-containing enzyme that aerobically catalyzes the four-electron oxidative ring closure reactions of delta-(L-alpha-aminoadipoyl)-L-cysteinyl-D-valine (ACV), forming the beta-lactam and thiazolidine rings of isopenicillin N [24].
• 1. Isopenicillin N synthetase (IPNS) from Cephalosporium acremonium, which requires Fe2+ and O2 for activity, was highly purified for studies of factors affecting its conversion of delta-(L-alpha-aminoadipoyl)-L-cysteinyl-D-valine (LLD-ACV) into isopenicillin N (IPN) [25].
• A 24-mer mixed-DNA probe based on the N-terminal amino-acid sequence of CLA was used to isolate the corresponding gene (cla), located near one end of the known cluster of penicillin and cephamycin biosynthetic genes, 5.7 kb downstream from the pcbC gene which encodes isopenicillin-N synthase [26].

Gene context of Penicillin M

• The PVA/U34 family is variable in sequence and exhibits great diversity in substrate specificity, to include enzymes such as choloyglycine hydrolases, acid ceramidases, isopenicillin N acyltransferases, and a subgroup of eukaryotic proteins with unclear function [27].
• The Phl protein contains the peroxisome-targeting sequence that is also present in the isopenicillin N acyltransferase [28].

Analytical, diagnostic and therapeutic context of Penicillin M

• All mutants showed normal levels of isopenicillin N synthase, as shown by Western blot analysis and enzyme assays (except npe10 that lacked this enzyme and npe2 and npe3 that formed reduced levels); npe1, npe4, npe6, npe7, npe8, and npe10 lacked isopenicillin N acyltransferase [29].
• Crystallization and preliminary X-ray diffraction studies on a recombinant isopenicillin N synthase from Cephalosporium acremonium [30].
• The isopenicillin N synthase formed after expression of the pcbC gene in the S. clavuligerus nce2 mutant strain was found to have an Mr of 38,000 by gel filtration [11].
• Thiolate ligation of the active site Fe2+ of isopenicillin N synthase derives from substrate rather than endogenous cysteine: spectroscopic studies of site-specific Cys----Ser mutated enzymes [31].
• Circular dichroism spectroscopy was employed to compare the conformation of pure flavanone 3beta-hydroxylase with that of isopenicillin N synthase [32].

References