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Gene Review

lamB  -  maltoporin

Escherichia coli UTI89

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Disease relevance of lamB

  • Escherichia coli strains have been isolated that produce hybrid proteins comprised of an NH2-terminal sequence from the lamB gene product (an outer membrane protein) and a major portion of the COOH-terminal sequence of beta-galactosidase (beta-D-galactoside galactohydrolase, EC; a cytoplasmic protein) [1].
  • Concatamers of random oligonucleotides were introduced into a portion of a plasmid-borne lamB gene encoding an external domain of the phage lambda receptor [2].
  • Protein Ia and the lamB protein can replace each other in the constitution of an active receptor for the same coliphage [3].
  • Expression of the lamB gene in Vibrio cholerae strain TRH7000 was not sufficient to permit cosmid transduction [4].
  • These vectors were tested by subcloning the xylE gene coding for the Pseudomonas putida catechol 2,3-oxygenase and the Escherichia coli lamB gene coding for the lambda receptor [4].

High impact information on lamB


Chemical compound and disease context of lamB

  • The phage lambda receptor, or LamB, proteins have been purified from several missense lamB mutants, and the properties of the channel produced by these proteins were investigated in a reconstituted liposome system [9].

Biological context of lamB

  • We have examined properties of synthetic peptides corresponding to a family of signal sequences derived from the lamB gene of Escherichia coli, including five examples of known phenotype that contain mutations in the signal sequence [10].
  • Southern-blot hybridization analysis established that both the EIEC strain and the K-12 strains with or without the virulence plasmid contained one lamB gene only, and no laminin-binding protein appeared when the virulence plasmid was introduced into bacteria deleted for the lamB gene [11].
  • Second, an operon fusion strain in which the lamB gene is expressed under lac promoter control was used; in this system, LamB protein can be induced by isopropyl-beta-D-thiogalactopyranoside [12].
  • Kinetics of induction of the lamB-gene product in Escherichia coli: appearance of the newly synthesized protein in the cell envelope [13].
  • DNA sequencing was performed as far as a HinfI restriction site located 1313 base-pairs downstream from gene lamB [14].

Associations of lamB with chemical compounds

  • However, with one exception, the most extreme effect of lamB mutants on the maltose response as determined in the capillary assay is a shift to higher sugar concentrations and a reduction in the number of bacteria accumulated to about 25% of the wild-type level [15].
  • FhuA delta335-355 rendered cells sensitive to sodium dodecyl sulfate and supported diffusion of maltotetraose and maltopentaose in a lamB mutant lacking the maltodextrin-specific channel in the outer membrane [16].
  • Maximal transport and lamB induction coincided with increased endogenous maltotriose (inducer) concentrations during growth on glucose [17].
  • LamB glycoporin has an important general role in carbohydrate uptake during growth at low extracellular sugar concentrations. lamB and mal regulon induction during glucose starvation and glucose-limited continuous culture was investigated using lacZ fusions [17].

Other interactions of lamB

  • The protein found in a second strain, pop 3186, contains much more of the lamB gene protein; a substantial fraction of the beta-galactosidase activity is found in the outer membrane, probably facing outward [1].

Analytical, diagnostic and therapeutic context of lamB

  • Multiplex PCR amplification using differing amounts of primers specific for lacZ and lamB genes permitted the detection of coliform bacteria and those associated with human faecal contamination, including the indicator bacterial species E. coli and enteric pathogens Salmonella and Shigella [18].


  1. Use of gene fusions to study outer membrane protein localization in Escherichia coli. Silhavy, T.J., Shuman, H.A., Beckwith, J., Schwartz, M. Proc. Natl. Acad. Sci. U.S.A. (1977) [Pubmed]
  2. Engineered iron oxide-adhesion mutants of the Escherichia coli phage lambda receptor. Brown, S. Proc. Natl. Acad. Sci. U.S.A. (1992) [Pubmed]
  3. Protein Ia and the lamB protein can replace each other in the constitution of an active receptor for the same coliphage. Wandersman, C., Schwartz, M. Proc. Natl. Acad. Sci. U.S.A. (1978) [Pubmed]
  4. A series of wide-host-range low-copy-number vectors that allow direct screening for recombinants. Morales, V.M., Bäckman, A., Bagdasarian, M. Gene (1991) [Pubmed]
  5. Genetic study of a membrane protein: DNA sequence alterations due to 17 lamB point mutations affecting adsorption of phage lambda. Clément, J.M., Lepouce, E., Marchal, C., Hofnung, M. EMBO J. (1983) [Pubmed]
  6. Synthesis and maturation of lambda receptor in Escherichia coli K-12: in vivo and in vitro expression of gene lamB under lac promoter control. Marchal, C., Perrin, D., Hedgpeth, J., Hofnung, M. Proc. Natl. Acad. Sci. U.S.A. (1980) [Pubmed]
  7. Specificity of diffusion channels produced by lambda phage receptor protein of Escherichia coli. Luckey, M., Nikaido, H. Proc. Natl. Acad. Sci. U.S.A. (1980) [Pubmed]
  8. Mutations altering the cellular localization of the phage lambda receptor, an Escherichia coli outer membrane protein. Emr, S.D., Schwartz, M., Silhavy, T.J. Proc. Natl. Acad. Sci. U.S.A. (1978) [Pubmed]
  9. Purification and functional characterization of mutant LamB proteins. Luckey, M., Nikaido, H. Ann. Microbiol. (Paris) (1982) [Pubmed]
  10. Functional and nonfunctional LamB signal sequences can be distinguished by their biophysical properties. McKnight, C.J., Briggs, M.S., Gierasch, L.M. J. Biol. Chem. (1989) [Pubmed]
  11. Binding of basement-membrane laminin by Escherichia coli. Valkonen, K.H., Veijola, J., Dagberg, B., Uhlin, B.E. Mol. Microbiol. (1991) [Pubmed]
  12. High-sensitivity detection of newly induced LamB protein on the Escherichia coli cell surface. Vos-Scheperkeuter, G.H., Hofnung, M., Witholt, B. J. Bacteriol. (1984) [Pubmed]
  13. Kinetics of induction of the lamB-gene product in Escherichia coli: appearance of the newly synthesized protein in the cell envelope. Kok, M., Vos Scheperkeuter, G., Witholt, B. Ann. Microbiol. (Paris) (1982) [Pubmed]
  14. malM, a new gene of the maltose regulon in Escherichia coli K12. I. malM is the last gene of the malK-lamB operon and encodes a periplasmic protein. Gilson, E., Rousset, J.P., Charbit, A., Perrin, D., Hofnung, M. J. Mol. Biol. (1986) [Pubmed]
  15. Role of the receptor for bacteriophage lambda in the functioning of the maltose chemoreceptor of Escherichia coli. Hazelbauer, G.L. J. Bacteriol. (1975) [Pubmed]
  16. Properties of the FhuA channel in the Escherichia coli outer membrane after deletion of FhuA portions within and outside the predicted gating loop. Killmann, H., Benz, R., Braun, V. J. Bacteriol. (1996) [Pubmed]
  17. Differential expression of mal genes under cAMP and endogenous inducer control in nutrient-stressed Escherichia coli. Notley, L., Ferenci, T. Mol. Microbiol. (1995) [Pubmed]
  18. Multiplex PCR amplification and immobilized capture probes for detection of bacterial pathogens and indicators in water. Bej, A.K., Mahbubani, M.H., Miller, R., DiCesare, J.L., Haff, L., Atlas, R.M. Mol. Cell. Probes (1990) [Pubmed]
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