Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.6 (RNA polymerase)
 34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recently, we reported the molecular cloning and nucleotide sequence analysis of a gene from Rickettsia rickettsii that codes for a 17-kilodalton antigen (17K antigen) and is preceded by sequences closely resembling the -10 and -35 consensus sequences for recognition by Escherichia coli RNA polymerase (Anderson et al., J. Bacteriol. 169:2385-2390, 1987). Experiments described in this report indicate that the start sites for initiating transcription of the 17K antigen gene are identical in the E. coli clone and in intact R. rickettsii. In each case, initiation was shown to begin 9 bases downstream of the presumed Pribnow box sequence (TATACT). A 169-base-pair fragment containing the promoter sequence initiated transcription in both directions when cloned into an E. coli promoter probe vector. The rickettsial fragment was found to contain sequences identical to the -10 region (but not the -35 region) of the E. coli promoter consensus sequence directed away from the 17K antigen gene. The amino-terminal portion (residues 17 to 20) of the deduced amino acid sequence for the 17K antigen contained the tetrapeptide Leu-Gln-Ala-Cys, a sequence that conforms favorably to those described for lipid modification and cleavage by lipoprotein signal peptidase II. The 17K antigen produced by the E. coli clone was shown to be labeled with [3H]palmitate and [3H]glycerol, indicative of lipid modification. In vitro mutagenesis designed to alter the cysteine at residue 20 to a glycine abolished incorporation of [3H]palmitate, suggesting that posttranslational modification occurs via a mechanism similar to that described for other gram-negative bacterial lipoproteins.
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PMID:Expression of the gene encoding the 17-kilodalton antigen from Rickettsia rickettsii: transcription and posttranslational modification. 313 29

The Vibrio cholerae (Vc) gene (tagA) coding for the TagA lipoprotein has been isolated. Sequencing of tagA revealed the presence of an open reading frame (ORF) of 568 amino acids with a characteristic signal peptidase II cleavage site at the N terminus. Electrophoretic analysis of proteins synthesized by Escherichia coli (Ec) cells following T7 promoter/RNA polymerase-directed expression of tagA, revealed a closely migrating doublet of proteins corresponding to two species of TagA. Computer-generated alignment algorithms predict that a homology exists between Vc TagA and Ec K99 fimbriae biogenesis determinant FanD.
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PMID:Isolation and characterization of a Vibrio cholerae gene (tagA) that encodes a ToxR-regulated lipoprotein. 788 90

rpoS is the structural gene for sigma s, which is a second vegetative sigma subunit of RNA polymerase in Escherichia coli and is involved in the expression of many stationary phase-induced genes. Upstream of rpoS is an open reading frame (ORF) whose function and regulation have not been studied. Strong overproduction of its gene product using the IPTG-inducible tac promoter leads to the formation of bulges at the cell septum and the cell poles, and in rapidly growing cells brings about cell lysis, indicating that the gene product has a hydrolytic function in cell wall formation or maintenance. This is corroborated by sequence homology to lysostaphin, a cell wall lytic exoenzyme synthesized by two Staphylococcus strains. Using globomycin, a specific inhibitor of signal peptidase II, we demonstrate that the product of the ORF is a novel lipoprotein (NlpD). Two transcriptional start sites for nlpD have been localized. In contrast to rpoS, nlpD is not induced during entry into stationary phase. Growth-phase-regulated transcription of rpoS is initiated at additional sites within the nlpD ORF, but the nlpD promoters contribute substantially to the basal level of rpoS expression in exponentially growing cells, indicating that nlpD and rpoS form an operon.
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PMID:The nlpD gene is located in an operon with rpoS on the Escherichia coli chromosome and encodes a novel lipoprotein with a potential function in cell wall formation. 799 84