Disease relevance of malE

• Maltose transport across the cytoplasmic membrane of Escherichia coli is dependent on the presence of a periplasmic maltose-binding protein (MBP), the product of the malE gene [1].
• The malE and malK genes from Salmonella typhimurium, and the malEFG operon and a portion of malK from Enterobacter aerogenes were cloned and sequenced [2].
• We fused the wild-type Agrobacterium tumefaciens virG gene and the constitutive virGN54D allele to the malE gene of Escherichia coli, and studied the binding of MBP-VirG fusions to the autoregulated virG promoter [3].
• The plasmid-encoded epidermin biosynthesis gene, epiD, of Staphylococcus epidermidis Tü3298 was expressed in Escherichia coli by using both the malE fusion system and the T7 RNA polymerase-promoter system [4].
• In one malE mutant known to be deficient in the transport of maltose and maltodextrins across the outer membrane, the altered MalE protein was shown to be defective in its interaction with the phage lambda receptor, or LamB protein, of the outer membrane [5].

High impact information on malE

• Deletion of these REP sequences from the chromosomal operon not only destabilizes upstream malE mRNA, but also results in a 9-fold reduction in the synthesis of MalE protein [6].
• Intragenic suppressor mutations of malE delta 12-18 have been obtained, some highly efficient in their ability to restore proper MBP export [7].
• A deletion mutation, malE delta 12-18, removes seven residues from the hydrophobic core of the maltose binding protein (MBP) signal peptide and thus prevents secretion of this protein to the periplasm of E. coli [7].
• Using a malE signal sequence mutant, which has a Mal-phenotype in secG mutant strains, we have isolated extragenic Mal+ suppressors [8].
• Mutations in any of the three high-affinity binding sites reduced both malEp and malKp activity [9].

Biological context of malE

• By sequencing upstream from malF, the malE-malF intercistronic region was found to be 153 base pairs in length and to contain inverted repeats, homologous to intercistronic repeats of many other operons [10].
• The nucleotide sequence of the gene for malF protein, an inner membrane component of the maltose transport system of Escherichia coli. Repeated DNA sequences are found in the malE-malF intercistronic region [10].
• The introduction of a plasmid carrying skc fused with malE (gene encoding maltose-binding protein) also induced cps-lacZ expression, but intracellular expression of streptokinase in E. coli did not [11].
• Nineteen mutations that still permit synthesis of stable MBP were generated by random insertion of a BamHI octanucleotide into malE and six additional mutations by in-vitro recombinations between mutant genes [12].
• The product of the malE-lacZ gene fusion was reported to compete with some proteins including outer membrane lipoprotein in the protein translocation across the Escherichia coli membrane [13].

Anatomical context of malE

• Maltose-binding protein (MBP), which is encoded by the malE gene, is the maltose chemoreceptor of Escherichia coli, as well as an essential component of the maltose uptake system [14].

Associations of malE with chemical compounds

• The sequences of the malE gene and of its mature product, the maltose-binding protein, have been determined and are in good agreement [15].
• The malE gene encodes the pre-protein (396 amino acid residues) which yields, upon cleavage of the NH2-terminal extension (26 amino acid residues), the mature maltose-binding protein (370 amino acid residues) [15].
• The induction of a specific abnormal malE-lacZ fusion protein, which is capable of disrupting the normal membrane protein secretion process, also increased the rate of killing by streptomycin [16].
• In the other study, dominant mutations in malE (the structural gene of MBP) were isolated; one of these altered the same tyrosine residue (210) to cysteine [17].
• These plasmids could be grouped into three classes, based upon their ability to complement in vivo a chromosomal malE deletion in the presence or absence of isopropyl thiogalactoside [18].

Physical interactions of malE

• Another fusion gene was generated by inserting ceaB3 between the malE gene encoding maltose binding protein (mbp) and lacZ alpha of the pmal-c2 vector [19].

Regulatory relationships of malE

• The in vivo synthesis and export of plasmid-encoded MBP were studied in the presence and absence of isopropyl thiogalactoside and maltose and in a strain harboring a prlA mutation that suppresses the malE signal sequence mutation and is thought to alter the export machinery of cells [18].
• Mutations previously designated prlD were described that suppressed malE signal sequence mutations and were located in the vicinity of the secA gene on the Escherichia coli chromosome [20].

Other interactions of malE

• To facilitate purification and characterization of SoxS, we constructed a fusion of soxS to malE, which encodes maltose-binding protein, and demonstrated that the in vivo expression of the MalE-SoxS fusion protein can provide SoxS function to a soxRS deletion mutant [21].
• Moreover, when expressed in attenuated aroA S. typhimurium strain SL3261, the plasmids carrying malE and malE-HIV genes were stable in vitro and in vivo [22].

Analytical, diagnostic and therapeutic context of malE

• To assess the molecular determinants of Kr resistance, the S. cinnamoneus tuf gene was expressed in Escherichia coli as a translational fusion to malE, which enabled the recovery by affinity chromatography of the recombinant protein uncontaminated by the host factor [23].

References