Disease relevance of melB

• The nucleotide sequence of the melB gene coding for the melibiose carrier in Escherichia coli has been determined [1].
• The melB gene coding for the melibiose carrier of Klebsiella pneumoniae was cloned and sequenced [2].

High impact information on melB

• The mutated gene, melB, of the mutants was cloned, and the nucleotide sequence was determined [3].
• The apparent molecular weight of the alpha-galactosidase (coded by melA) was about 50,000 and that of the melibiose carrier (coded by melB) was about 31,000, as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis [4].
• Nucleotide sequence of the melB gene and characteristics of deduced amino acid sequence of the melibiose carrier in Escherichia coli [1].
• Membrane topology of the melibiose permease of Escherichia coli studied by melB-phoA fusion analysis [5].
• Mel-6His permease was constructed by modifying the permease gene (melB) in vitro and then overproduced in cells transformed with multicopy plasmids [6].

Chemical compound and disease context of melB

• The melibiose transport carrier of Escherichia coli (coded by melB gene) is a cotransport system which couples the transport of a-galactosides to protons, sodium, or lithium ions [7].

Biological context of melB

• Genetic complementation tests and recombination analyses using those plasmids and melA- and melB- mutants as well as biochemical analyses of mel mutants transformed with those plasmids enabled us to determine the physical location of promoter, melA, and melB on the DNA segment [4].
• This DNA portion seems to be responsible for reduced expression of melB, the second gene of the melibiose operon [8].

Anatomical context of melB

• By use of techniques described recently for lac permease [Roepe, P.D., & Kaback, H.R. (1989) Proc. Natl. Acad. Sci. U.S.A. 86, 6087], the melibiose permease from Escherichia coli, another polytopic integral plasma membrane protein, has been purified in a metastable soluble form after overexpression of the melB gene via the T7 RNA polymerase system [9].

Analytical, diagnostic and therapeutic context of melB

• Asp124 in membrane-spanning helix IV of the carrier protein was replaced with Ser, Ile or Phe by site-directed mutagenesis of a plasmid containing the melB gene [10].

References