Proline transport carrier-defective mutants of Escherichia coli K-12: properties and mapping.
AUTOR(ES)
Motojima, K
RESUMO
A series of mutants of Escherichia coli K-12 requiring a high concentration of L-proline for growth were isolated from a proline auxotroph strain, JE2133. Genetic studies of the mutants, PT19, PT21, and PT22, showed that all the mutations (proT) were point mutations, and these were mapped at 82 min on the E. coli genetic map. Intact cells and cytoplasmic membrane vesicles of these mutants were specifically defective in L-proline transport activity. Strain PT21 had no detectable activity of the L-proline transport carrier at all, and strains PT19 and PT22 had only 1/35 and 1/70, respectively, of the transport activity of the parental strain. The mutants were also shown to have a defect in proline-binding function of the carrier by measuring specific binding of proline to sonically disrupted membranes. These results indicate that the gene proT determines the function of proline carrier in the cytoplasmic membrane.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=218625Documentos Relacionados
- Mutations affecting transport of the hexitols D-mannitol, D-glucitol, and galactitol in Escherichia coli K-12: isolation and mapping.
- Genetic and biochemical studies of transport systems for branched-chain amino acids in Escherichia coli K-12: isolation and properties of mutants defective in leucine-repressible transport activities.
- gamma-Glutamyltranspeptidase from Escherichia coli K-12: purification and properties.
- Some Properties of Excision-defective Recombination-deficient Mutants of Escherichia coli K-12
- A new pleiotropic mutation causing defective carbohydrate uptake in Escherichia coli K-12: isolation, mapping, and preliminary characterization.