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J E González-Pastor

Publications and source records attributed to J E González-Pastor.

6 recordsLinked to original sources
PubMed2001

Fruiting body formation by Bacillus subtilis.

Spore formation by the bacterium Bacillus subtilis has long been studied as a model for cellular differentiation, but predominantly as a single cell. When analyzed within the context of highly structured, surface-associated communities (biofilms), spore formation was discovered to have heretofore unsuspected spatial organization. Initially, motile cells differentiated into aligned chains of attached cells that eventually produced aerial structures, or fruiting bodies, that served as preferential sites for sporulation. Fruiting body formation depended on regulatory genes required early in sporulation and on genes evidently needed for exopolysaccharide and surfactin production. The formation of aerial structures was robust in natural isolates but not in laboratory strains, an indication that multicellularity has been lost during domestication of B. subtilis. Other microbial differentiation processes long thought to involve only single cells could display the spatial organization characteristic of multicellular organisms when studied with recent natural isolates.

Bacillus subtilis↗
PubMed1999

Sequence analysis of the four plasmid genes required to produce the circular peptide antibiotic microcin J25.

A 4.8-kb plasmid region carrying the four genes mcjABCD necessary for production of and immunity to the cyclic peptide antibiotic microcin J25 (MccJ25) has been sequenced. mcjA encodes the primary structure of MccJ25 as a precursor endowed with an N-terminal extension of 37 amino acids. The products of mcjB and mcjC are thought to be involved in microcin maturation, which implies cleavage of McjA and head-tail linkage of the 21-residue pro-MccJ25. The predicted McjD polypeptide, which is highly similar to several ABC exporters, was found to be required for MccJ25 secretion, thus explaining its ability to confer immunity to MccJ25.

ATP-Binding Cassette Transporters↗
PubMed1995

Chemical structure and translation inhibition studies of the antibiotic microcin C7.

Escherichia coli microcin C7 (MccC7) is an antibiotic that inhibits protein synthesis in vivo. It is a heptapeptide containing unknown modifications at the N and C termini (García-Bustos, J. F., Pezzi, N., and Méndez, E. (1985) Antimicrob. Agents Chemoth. 27, 791-797). The chemical structure of MccC7 has been characterized by use of 1H homonuclear and heteronuclear (13C, 15N, 31P) nuclear magnetic resonance spectroscopy as well as mass spectrometry (1177 +/- 1 Da). The heptapeptide Met-Arg-Thr-Gly-Asn-Ala-Asp is substituted at the N terminus by a N-formyl group. The C-terminal substituent consists of the phosphodiester of 5'-adenylic acid and n-aminopropanol (AMPap), which is linked via the phosphorus atom to an amide group, thus forming a phosphoramide. The main chain carbonyl of the C-terminal aspartic acid residue is connected via this amide bond to the modified nucleotide unit. MccC7 and the peptide unit inhibit protein translation in vitro while a synthetic analog of the AMPap substituent is not active. Neither the peptide nor the AMPap molecule has an effect on the growth of MccC7-sensible cells. Our results strongly suggest that the peptide is responsible for MccC7 antibiotic activity while the C-terminal substituent is needed for MccC7 transport. Implications of the structure determined in this work for MccC7 synthesis and mode of action are discussed.

Amino Acid Sequence↗
PubMed1995

Structure and organization of plasmid genes required to produce the translation inhibitor microcin C7.

The translation inhibitor microcin C7 (MccC7) is a linear heptapeptide whose N terminus has been replaced by an N-formyl group and whose C terminus has been replaced by the phosphodiester of 5'-adenylic acid and n-aminopropanol (J. I. Guijarro, J. E. González-Pastor, F. Baleux, J. L. San Millán, M. A. Castilla, M. Rico, F. Moreno, and M. Delepierre, J. Biol. Chem. 270:23520-23532, 1995). MccC7 production and immunity determinants lie on a 6.2-kb region of the Escherichia coli plasmid pMccC7. This region was entirely sequenced. It contains six open reading frames, which were shown to be true genes by different complementary approaches. Five genes, mccABCDE, which are transcribed in the same direction, are required to produce mature extracellular microcin. The sixth gene, mccF, adjacent to mccE, is transcribed in the opposite direction and encodes specific self-immunity. Genes mccA to -E constitute an operon transcribed from a promoter (mccp) located upstream of mccA. mccA is 21 nucleotides long and encodes the unmodified heptapeptide (J. E. González-Pastor, J. L. San Millán, and F. Moreno, Nature [London] 369:281, 1994). A comparison of predicted gene polypeptide products with those included in databases shows that an 81-amino-acid stretch of MccB is strikingly homologous to fragments of the same length of proteins ThiF and ChlN from E. coli, HesA from Anabaena sp. strain PCC7120, and UBA1, the ubiquitin-activating enzyme from different eukaryotic species. MccC displays several hydrophobic domains, suggesting a transmembrane location. The carboxyl end of MccE displays 41.2% identity with RimL, a protein required to acetylate the ribosome protein L12 from E. coli. In the absence of the other mcc genes, mccA impairs the growth of host cells, suggesting that unmodified MccA has antibiotic activity. A model for MccC7 biosynthesis, export, and immunity is proposed.

Amino Acid Sequence↗
PubMed1991

Nucleotide sequence of the Escherichia coli regulatory gene mprA and construction and characterization of mprA-deficient mutants.

In high copy number, the Escherichia coli mprA gene reduces the synthesis of peptide microcins B17 and C7 (MccB17 and MccC7) and blocks the osmoinduction of the proU operon at the transcriptional level. mprA has been sequenced and shown to encode a polypeptide of 176 amino acids (Mr, 20,563). Insertion and deletion mutant mprA alleles were constructed and then transferred to the chromosome by allelic replacement. In these mutants, expression of two mcb-lacZ fusions was fivefold derepressed, indicating a negative regulatory role of mprA on the mcb operon (MccB17). In contrast, no effect of the MprA- mutations on the expression of mcc operon (MccC7) or on the osmoinduction of proU operon was observed.

Alleles↗