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. 1977 Sep;131(3):830–838. doi: 10.1128/jb.131.3.830-838.1977

Isolation, genetic analysis, and characterization of Escherichia coli mutants with defects in the lacY gene.

A C Hobson, D Gho, B Müller-Hill
PMCID: PMC235538  PMID: 330501

Abstract

Five hundred thirty-five lacY mutants were isolated from an Escherichia coli strain carrying the lactose operon on an F' factor, either without mutagenesis or after mutagenesis with 2-aminopurine or N-methyl-N'-nitro-N-nitrosoguanidine. Crosses against 48 independently isolated deletions ending in the lacY gene divided the gene into 36 deletion groups. Suppressibility studies with 7 nonsense suppressor strains classified 276 mutants as nonsense mutants and 78 as missense (or nonsuppressible) mutants. One hundred seventy-nine mutants were "leaky" and could not be so allocated, and two were found to have small internal deletions. Nonsense mutants could in many cases be subdivided even within deletion groups on the basis of their suppressibility pattern, giving a total of 70 groups of nonsense mutants. Studies of these mutants allow the following conclusions: lactose and melibiose most probably do not have separate binding sites on the permease; the lacY region most likely consists of one cistron, and so both active transport and facilitated diffusion are functions of one protein; and finally, there is probably no small defined region of the permease responsible for energy coupling of transport. Furthermore, the strains and the analysis form the basis for a future functional study of the permease by biochemical techniques.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Buttin G. Les systemes enzymatiques inductibles du metabolisme des oses chez Escherichia coli. Adv Enzymol Relat Areas Mol Biol. 1968;30:81–137. [PubMed] [Google Scholar]
  2. Carter J. R., Fox C. F., Kennedy E. P. Interaction of sugars with the membrane protein component of the lactose transport system of Escherichia coli. Proc Natl Acad Sci U S A. 1968 Jun;60(2):725–732. doi: 10.1073/pnas.60.2.725. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Fox C. F., Carter J. R., Kennedy E. P. GENETIC CONTROL OF THE MEMBRANE PROTEIN COMPONENT OF THE LACTOSE TRANSPORT SYSTEM OF Escherichia coli. Proc Natl Acad Sci U S A. 1967 Mar;57(3):698–705. doi: 10.1073/pnas.57.3.698. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Fox C. F., Kennedy E. P. Specific labeling and partial purification of the M protein, a component of the beta-galactoside transport system of Escherichia coli. Proc Natl Acad Sci U S A. 1965 Sep;54(3):891–899. doi: 10.1073/pnas.54.3.891. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Gho D., Miller J. H. Deletions fusing the i and lac regions of the chromosome in E. coli: isolation and mapping. Mol Gen Genet. 1974;131(2):137–146. doi: 10.1007/BF00266149. [DOI] [PubMed] [Google Scholar]
  6. Gorini L. Informational suppression. Annu Rev Genet. 1970;4:107–134. doi: 10.1146/annurev.ge.04.120170.000543. [DOI] [PubMed] [Google Scholar]
  7. Gottesman S., Beckwith J. R. Directed transposition of the arabinose operon: a technique for the isolation of specialized transducing bacteriophages for any Escherichia coli gene. J Mol Biol. 1969 Aug 28;44(1):117–127. doi: 10.1016/0022-2836(69)90408-2. [DOI] [PubMed] [Google Scholar]
  8. KOCH A. L. THE ROLE OF PERMEASE IN TRANSPORT. Biochim Biophys Acta. 1964 Jan 27;79:177–200. doi: 10.1016/0926-6577(64)90050-6. [DOI] [PubMed] [Google Scholar]
  9. Langridge J. Characterization and intragenic position of mutations in the gene for galactoside permease of Escherichia coli. Aust J Biol Sci. 1974 Jun;27(3):331–340. doi: 10.1071/bi9740331. [DOI] [PubMed] [Google Scholar]
  10. Malamy M. H. Frameshift mutations in the lactose operon of E. coli. Cold Spring Harb Symp Quant Biol. 1966;31:189–201. doi: 10.1101/sqb.1966.031.01.027. [DOI] [PubMed] [Google Scholar]
  11. Miller J. H., Reznikoff W. S., Silverstone A. E., Ippen K., Signer E. R., Beckwith J. R. Fusions of the lac and trp Regions of the Escherichia coli Chromosome. J Bacteriol. 1970 Dec;104(3):1273–1279. doi: 10.1128/jb.104.3.1273-1279.1970. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Mitchell P. Performance and conservation of osmotic work by proton-coupled solute porter systems. J Bioenerg. 1973 Jan;4(1):63–91. doi: 10.1007/BF01516051. [DOI] [PubMed] [Google Scholar]
  13. Müller-Hill B. Lac repressor and lac operator. Prog Biophys Mol Biol. 1975;30(2-3):227–252. doi: 10.1016/0079-6107(76)90011-0. [DOI] [PubMed] [Google Scholar]
  14. Pfahl M. Genetic map of the lactose repressor gene (i) of Escherichia coli. Genetics. 1972 Nov;72(3):393–410. doi: 10.1093/genetics/72.3.393. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Purdy D. R., Koch A. L. Energy cost of galactoside transport to Escherichia coli. J Bacteriol. 1976 Sep;127(3):1188–1196. doi: 10.1128/jb.127.3.1188-1196.1976. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Schuldiner S., Kaback H. R. Membrane potential and active transport in membrane vesicles from Escherichia coli. Biochemistry. 1975 Dec 16;14(25):5451–5461. doi: 10.1021/bi00696a011. [DOI] [PubMed] [Google Scholar]
  17. Smith J. D., Barnett L., Brenner S., Russell R. L. More mutant tyrosine transfer ribonucleic acids. J Mol Biol. 1970 Nov 28;54(1):1–14. doi: 10.1016/0022-2836(70)90442-0. [DOI] [PubMed] [Google Scholar]
  18. Wilson T. H., Kusch M., Kashket E. R. A mutant in Escherichia coli energy-uncoupled for lactose transporta defect in the lactose-operon. Biochem Biophys Res Commun. 1970 Sep 30;40(6):1409–1414. doi: 10.1016/0006-291x(70)90024-0. [DOI] [PubMed] [Google Scholar]
  19. Wong P. T., Kashket E. R., Wilson T. H. Energy coupling in the lactose transport system of Escherichia coli. Proc Natl Acad Sci U S A. 1970 Jan;65(1):63–69. doi: 10.1073/pnas.65.1.63. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Yanofsky C., Cox E. C., Horn V. The unusual mutagenic specificity of an E. Coli mutator gene. Proc Natl Acad Sci U S A. 1966 Feb;55(2):274–281. doi: 10.1073/pnas.55.2.274. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Zipser D., Zabell S., Rothman J., Grodzicker T., Wenk M. Fine structure of the gradient of polarity in the z gene of the lac operon of Escherichia coli. J Mol Biol. 1970 Apr 14;49(1):251–254. doi: 10.1016/0022-2836(70)90392-x. [DOI] [PubMed] [Google Scholar]

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