Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0519030 (Klebsiella)
 21,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vibrio cholerae secretes a number of proteins important for virulence, including cholera toxin. This process requires the products of the eps genes which have homologues in genera such as Aeromonas, Klebsiella and Pseudomonas and are thought to form a membrane-associated multiprotein complex. Here we show that the putative nucleotide-binding protein EpsE is associated with and stabilized by the cytoplasmic membrane via interaction with EpsL. Analysis of fusion proteins between EpsE and the homologous ExeE from Aeromonas hydrophila demonstrates that the N-terminus of EpsE contains the EpsL binding domain and determines species specificity. An intact Walker A box, commonly found in ATP-binding proteins, is required for activity of EpsE in vivo and for autophosphorylation of purified EpsE in vitro. These results indicate that both the kinase activity of EpsE as well as its ability to interact with the putative cytoplasmic membrane protein EpsL are required for translocation of toxin across the outer membrane in Vibrio cholerae.
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PMID:Interaction between the autokinase EpsE and EpsL in the cytoplasmic membrane is required for extracellular secretion in Vibrio cholerae. 773 19

pulE, one of 14 genes specifically required for pullulanase secretion in Klebsiella oxytoca, codes for a putative nucleotide-binding protein. Subcellular fractionation indicated that the majority of PulE in Escherichia coli cells expressing all 14 secretion genes is mainly associated with the cytoplasmic membrane through both hydrophobic and non-hydrophobic interactions. Mutational analysis revealed that one of the two regions of PulE that are conserved in many nucleotide-binding proteins (Walker box A) is essential for pullulanase secretion. Likewise, mutations that removed aspartate residues from each of two regions immediately downstream from the Walker box A also reduced secretion. These aspartate-rich regions are highly conserved in all 16 known PulE homologues but not in any other nucleotide-binding proteins. Altogether, these results indicate that PulE might belong to a new family of nucleotide-binding proteins. The protein could not be cross-linked to the photoactivatable ATP analogue azido-ATP, however. Most pulE point or deletion mutations which prevented pullulanase secretion exhibited transdominance when expressed at high levels in cells producing wild-type PulE protein. Evidence presented suggests that PulE might be a homodimer.
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PMID:Molecular characterization of PulE, a protein required for pullulanase secretion. 805 53

An ATP-binding cassette (ABC) transporter-dependent mechanism is responsible for the biosynthesis of polysaccharide O antigens in the lipopolysaccharides of many Gram-negative bacteria. In the Escherichia coli O9a prototype, addition of a non-reducing terminal modification regulates chain length. The terminal residue is an export signal recognized by the nucleotide-binding domain component of the cognate ABC transporter. The Klebsiella pneumoniae O2a antigen lacks a capping residue, and the corresponding nucleotide-binding protein does not contain a separate substrate-binding domain. Unlike the O9a transporter, the O2a transporter can export heterologous O antigens. Export of the O2a antigen is obligatorily coupled to chain elongation, and the O2a transporter is essential for establishing O antigen chain length. The E. coli O9a transporter operates after chain length has been determined. Furthermore biosynthesis and export can be uncoupled. O antigen chain length is a critical element in the ability of lipopolysaccharides to confer resistance to complement-mediated killing. This study establishes that two distinctly different approaches are available for the regulation of O antigen chain length and export via an ABC transporter.
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PMID:The Klebsiella pneumoniae O2a antigen defines a second mechanism for O antigen ATP-binding cassette transporters. 1903 29