The Structural Gene for Microcin H47 Encodes a Peptide Precursor with Antibiotic Activity

ABSTRACT Microcin H47 is a bactericidal antibiotic produced by a naturally occurring Escherichia coli strain isolated in Uruguay. The microcin genetic system is located in the chromosome and extends over a 10-kb DNA segment containing the genes required for microcin synthesis, secretion, and immunity. The smallest microcin synthesis gene,mchB, was sequenced and shown to encode a highly hydrophobic peptide. An mchB-phoA gene fusion, which directed the synthesis of a hybrid bifunctional protein with both PhoA and microcin H47-like activities, was isolated. The results presented herein lead us to propose that microcin H47 is indeed a ribosomally synthesized peptide antibiotic and that its peptide precursor already has antibiotic activity of the same specificity as that of mature microcin.

Download Full-text

The Structure, Function, and Origin of the Microcin H47 ATP-Binding Cassette Exporter Indicate Its Relatedness to That of Colicin V

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.45.3.969-972.2001 ◽

2001 ◽

Vol 45 (3) ◽

pp. 969-972 ◽

Cited By ~ 29

Author(s):

Marı́a F. Azpiroz ◽

Eliana Rodrı́guez ◽

Magela Laviña

Keyword(s):

Escherichia Coli ◽

Structure Function ◽

Gene Fusion ◽

Atp Binding ◽

Peptide Antibiotic ◽

Heterologous Complementation ◽

Colicin V ◽

Atp Binding Cassette

ABSTRACT Microcin H47, a gene-encoded peptide antibiotic produced by a natural Escherichia coli strain, was shown to be secreted by a three-component ATP-binding cassette exporter which was revealed to be strongly related to that of colicin V. The results of sequence and gene fusion analyses, as well as heterologous complementation assays, are presented.

Download Full-text

Genetic analysis of microcin H47 immunity

Canadian Journal of Microbiology ◽

10.1139/w98-044 ◽

1998 ◽

Vol 44 (7) ◽

pp. 692-697 ◽

Cited By ~ 18

Author(s):

Eliana Rodríguez ◽

Magela Laviña

Keyword(s):

Gene Fusion ◽

Genetic System ◽

Cellular Membrane ◽

Peptide Analysis ◽

Extracellular Medium ◽

Hybrid Proteins ◽

Site Of Action ◽

Membrane Peptide ◽

Highly Hydrophobic

Microcin H47 is a bactericidal antibiotic produced by a natural Escherichia coli isolate. The genetic system encoding microcin production and immunity consists of at least seven clustered genes. Four of these are devoted to microcin biosynthesis and two genes are required for its secretion into the extracellular medium. The product of the seventh gene, mchI, determines the cell's self-immunity. This gene was shown to encode a highly hydrophobic 69-residue peptide. Analysis of the MchI amino acid sequence, as well as the characterization of MchIPhoA hybrid proteins, indicated that the microcin immunity product is probably exported out of the cytoplasm and remains an integral membrane peptide. This localization of the immunity peptide points to the cellular membrane as the site of action of microcin H47. Key words: microcin H47, microcin immunity, phoA gene fusion, membrane peptide.

Download Full-text

Similarity Between the Amino-Terminal Portion of Mammalian 58-kD Sterol Carrier Protein (SCPx) and Escherichia coli Acetyl-CoA Acyltransferase: Evidence for a Gene Fusion in SCPx

DNA and Cell Biology ◽

10.1089/dna.1991.10.695 ◽

1991 ◽

Vol 10 (9) ◽

pp. 695-698 ◽

Cited By ~ 8

Author(s):

MICHAEL E. BAKER ◽

JEFFREY T. BILLHEIMER ◽

JEROME F. STRAUSS III

Keyword(s):

Escherichia Coli ◽

Gene Fusion ◽

Carrier Protein ◽

Sterol Carrier Protein ◽

Terminal Portion ◽

Acetyl Coa ◽

Amino Terminal

Download Full-text

Biosensor studies of collagen and laminin binding with immobilized Escherichia coli O157:H7 and inhibition with naturally occurring food additives

10.1117/12.335769 ◽

1999 ◽

Cited By ~ 3

Author(s):

Marjorie B. Medina

Keyword(s):

Escherichia Coli ◽

Food Additives ◽

Escherichia Coli O157 ◽

Naturally Occurring ◽

Laminin Binding

Download Full-text

SOS induction of selected naturally occurring substances in Escherichia coli (SOS chromotest)

Mutation Research/Genetic Toxicology and Environmental Mutagenesis ◽

10.1016/s1383-5718(99)00141-2 ◽

1999 ◽

Vol 445 (1) ◽

pp. 81-91 ◽

Cited By ~ 98

Author(s):

Sebastian Kevekordes ◽

Volker Mersch-Sundermann ◽

Christian M Burghaus ◽

Jan Spielberger ◽

Heinz H Schmeiser ◽

...

Keyword(s):

Escherichia Coli ◽

Sos Induction ◽

Naturally Occurring ◽

Sos Chromotest

Download Full-text

Plasmid pEC156, a Naturally Occurring Escherichia coli Genetic Element That Carries Genes of the EcoVIII Restriction-Modification System, Is Mobilizable among Enterobacteria

PLoS ONE ◽

10.1371/journal.pone.0148355 ◽

2016 ◽

Vol 11 (2) ◽

pp. e0148355 ◽

Cited By ~ 9

Author(s):

Olesia Werbowy ◽

Tadeusz Kaczorowski

Keyword(s):

Escherichia Coli ◽

Genetic Element ◽

Modification System ◽

Restriction Modification System ◽

Naturally Occurring ◽

Restriction Modification

Download Full-text

Insect-Mediated Dispersal of the Rhizobacterium Pseudomonas chlororaphis

Phytopathology ◽

10.1094/phyto.1998.88.12.1248 ◽

1998 ◽

Vol 88 (12) ◽

pp. 1248-1254 ◽

Cited By ~ 10

Author(s):

William E. Snyder ◽

David W. Tonkyn ◽

Daniel A. Kluepfel

Keyword(s):

Escherichia Coli ◽

Adult Stage ◽

Genetically Modified ◽

Insect Pest ◽

Corn Rootworm ◽

Transmission Route ◽

Pseudomonas Chlororaphis ◽

Naturally Occurring ◽

Southern Corn Rootworm ◽

Corn Plants

The southern corn rootworm, Diabrotica undecimpunctata subsp. howardi, a common and mobile insect pest, was shown to transmit the rhizobacte-rium Pseudomonas chlororaphis strain L11 between corn plants. Strain L11 has been genetically modified to contain the lacZY genes from Escherichia coli. It can reach high densities on roots and invade the roots and move into the foliage. D. undecimpunctata subsp. howardi became infested with L11 as larvae while feeding on roots of seed-inoculated corn and retained the bacteria through pupation, molting to the adult stage, and emergence from the soil. Bacterial densities on or in the insects increased 100-fold after they fed again as adults on L11-infested foliage. Adults retained the bacteria for at least 2 weeks after last exposure and could transmit L11 to new plants. The likelihood of transmission decreased with time since last exposure to L11, but increased with time spent on the new plants. This research demonstrates that rhizobacteria can escape the rhizosphere by moving in or onto foliage, where they can then be acquired and transmitted by insects. This transmission route may be common among naturally occurring rhizobacteria and facilitate the dispersal of both beneficial and harmful soilborne microorganisms.

Download Full-text

The Leucine-Responsive Regulatory Protein, Lrp, Modulates Microcin J25 Intrinsic Resistance in Escherichia coli by Regulating Expression of the YojI Microcin Exporter

Journal of Bacteriology ◽

10.1128/jb.01074-08 ◽

2008 ◽

Vol 191 (4) ◽

pp. 1343-1348 ◽

Cited By ~ 9

Author(s):

Sergio B. Socías ◽

Paula A. Vincent ◽

Raúl A. Salomón

Keyword(s):

Escherichia Coli ◽

Efflux Pump ◽

Regulatory Protein ◽

Peptide Antibiotic ◽

Intrinsic Resistance ◽

Positive Regulator ◽

K 12 ◽

Microcin J25 ◽

Increased Susceptibility

ABSTRACT Many Escherichia coli K-12 strains display an intrinsic resistance to the peptide antibiotic microcin J25. In this study, we present results showing that the leucine-responsive regulatory protein, Lrp, is involved in this phenotype by acting as a positive regulator of YojI, a chromosomally encoded efflux pump which expels microcin out of cells. Exogenous leucine antagonizes the effect of Lrp, leading to a diminished expression of the pump and an increased susceptibility to microcin J25.

Download Full-text