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 3.2.1.23; 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

• We have determined the DNA sequence alterations of 17 lamB point mutations which result in resistance to phage lambda h+ [5].
• The lambda receptor is an outer membrane protein from Escherichia coli K-12 lamB, its structural gene, is part of the maltose regulon [6].
• In an equilibrium retention assay with reconstituted vesicles containing phospholipids and lipopolysaccharide, the lamB protein conferred permeability for disaccharides [7].
• The lamB protein, the receptor for phage lambda, was purified from the outer membrane of Escherichia coli K-12 by extraction with Triton X-100 and EDTA, chromatography on DEAE-Sephacel in Triton X-100, exchange of Triton for cholate by gel filtration, and chromatography on Sephacryl S-200 in cholate, NaCl, and EDTA [7].
• The other mutation behaves as a point mutation; when it is present in an otherwise normal lamB gene, reversion can be demonstrated [8].

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].

References