Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

With a DNA fragment from within the region encoding the transport functions for K1 production as a hybridization probe in Southern blot experiments, homologous DNA sequences were detected in the DNA from Escherichia coli strains producing K5, K7, K92, and K100 capsular polysaccharides. No homology with the laboratory strain LE392 was detected. The same DNA probe was used to prescreen cosmid libraries in LE392 by colony hybridization, as a rapid method to isolate clones encoding the genes for K5, K7, K12, and K92 antigen production. Clones carrying sequences homologous to the probe that also produced capsular material were identified by using polyclonal and monoclonal antibodies raised against the K antigen in question and K antigen-specific phages. By restriction enzyme mapping of the appropriate cosmid clones it was possible to align the genes for the production of different K antigens in terms of common restriction endonuclease cleavage sites. A DNA fragment encoding the postulated transport functions for K7 antigen production could complement deletion mutations in the transport functions for K1 antigen production. Thus the transport to the cell surface of chemically distinct polysaccharides may be by a common process. Analysis in E. coli of the proteins produced by plasmids carrying the likely transport functions for K1, K5, and K7 antigen production revealed that each region coded for a similar polypeptide.
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PMID:Molecular cloning and analysis of genes for production of K5, K7, K12, and K92 capsular polysaccharides in Escherichia coli. 302

All 62 Escherichia coli strains possessing the K1 capsular polysaccharide contained plasmid deoxyribonucleic acid, and most (51 of 62) had multiple plasmid species. The incidence of hemolysins, colicins, hemagglutinins for human erythrocytes, and plasmids did not differ among K1 strains isolated from the cerebrospinal fluids of neonates with meningitis or among those strains isolated from the stools of healthy individuals of all ages. There was an association between E. coli serotype and the distribution of plasmids, hemolysins, and colicins among the K1 strains. A common plasmid of about 65 megadaltons was found in all of the O18 serotypes; the similarity of these plasmids was confirmed by analysis with the restriction endonuclease EcoRI. Plasmids of similar molecular weight were also present in E. coli strains of the O7:K1 and O75:K100 serogroups. These data are consistent with the hypothesis that E. coli strains of the same serotype may be descendents of a single bacterial clone.
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PMID:Comparative analysis of plasmids and some metabolic characteristics of Escherichia coli K1 from diseased and healthy individuals. 699 36