Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0348321 (Haemophilus)
 15,372 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

DNA sequence analysis of a 1878-bp DNA fragment located downstream from the Rhizobium etli ptsN gene revealed the presence of an open reading frame coding for a protein of 300 amino acids. This protein is homologous to members of the PfkB subfamily of carbohydrate and carbohydrate phosphate kinases. Since the highest homology is observed with the ribokinases of Escherichia coli, Haemophilus influenzae and Bacillus subtilis, the isolated gene was named the R. etli rbsK gene. The eubacterial ribokinases form a cluster distinct from the cluster of ribokinase proteins of the archaebacteria Methanobacterium thermoautotrophicum, Methanococcus jannaschii and Sulfolobus solfoataricus, which form a more divergent group of proteins. R. etli RbsK has a molecular mass of 30.6 kDa and a calculated isoelectric point of 4.5. No homologues of Escherichia coli ORF284 and ORF90 were found downstream from R. etli ptsN.
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PMID:Sequence analysis of the Rhizobium etli ribose kinase gene rbsK and its phylogenetic position. 1052 58

The intermediate steps in the biosynthesis of the ADP-L-glycero-D-manno-heptose precursor of inner core lipopolysaccharide (LPS) are not yet elucidated. We isolated a mini-Tn10 insertion that confers a heptoseless LPS phenotype in the chromosome of Escherichia coli K-12. The mutation was in a gene homologous to the previously reported rfaE gene from Haemophilus influenzae. The E. coli rfaE gene was cloned into an expression vector, and an in vitro transcription-translation experiment revealed a polypeptide of approximately 55 kDa in mass. Comparisons of the predicted amino acid sequence with other proteins in the database showed the presence of two clearly separate domains. Domain I (amino acids 1 to 318) shared structural features with members of the ribokinase family, while Domain II (amino acids 344 to 477) had conserved features of the cytidylyltransferase superfamily that includes the aut gene product of Ralstonia eutrophus. Each domain was expressed individually, demonstrating that only Domain I could complement the rfaE::Tn10 mutation in E. coli, as well as the rfaE543 mutation of Salmonella enterica SL1102. DNA sequencing of the rfaE543 gene revealed that Domain I had one amino acid substitution and a 12-bp in-frame deletion resulting in the loss of four amino acids, while Domain II remained intact. We also demonstrated that the aut::Tn5 mutation in R. eutrophus is associated with heptoseless LPS, and this phenotype was restored following the introduction of a plasmid expressing the E. coli Domain II. Thus, both domains of rfaE are functionally different and genetically separable confirming that the encoded protein is bifunctional. We propose that Domain I is involved in the synthesis of D-glycero-D-manno-heptose 1-phosphate, whereas Domain II catalyzes the ADP transfer to form ADP-D-glycero-D-manno-heptose.
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PMID:The rfaE gene from Escherichia coli encodes a bifunctional protein involved in biosynthesis of the lipopolysaccharide core precursor ADP-L-glycero-D-manno-heptose. 1062 97