Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:6.3.5.5 (CPS)
 1,262 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report the identification of Integration Host Factor (IHF) as a new element involved in modulation of P1, the upstream pyrimidine-specific promoter of the Escherichia coli K12 and Salmonella typhimurium carAB operons. Band-shift assays, performed with S-30 extracts of the wild type and a himA, hip double mutant or with purified IHF demonstrate that, in vitro, this factor binds to a region 300 bp upstream of the transcription initiation site of P1 in both organisms. This was confirmed by deletion analysis of the target site. DNase I, hydroxyl radical and dimethylsulphate footprinting experiments allowed us to allocate the IHF binding site to a 38 bp, highly A+T-rich stretch, centred around nucleotide -305 upstream of the transcription initiation site. Protein-DNA contacts are apparently spread over a large number of bases and are mainly located in the minor groove of the helix. Measurements of carbamoyl-phosphate synthetase (CPSase) and beta-galactosidase specific activities from car-lacZ fusion constructs of wild type or IHF target site mutants introduced into several genetic backgrounds affected in the himA gene or in the pyrimidine-mediated control of P1 (carP6 or pyrH+/-), or in both, indicate that, in vivo, IHF influences P1 activity as well as its control by pyrimidines. IHF stimulates P1 promoter activity in minimal medium, but increases the repressibility of this promoter by pyrimidines. These antagonistic effects result in a two- to threefold reduction in the repressibility of promoter P1 by pyrimidines in the absence of IHF binding. IHF thus appears to be required for maximal expression as well as for establishment of full repression. IHF could exert this function by modulating the binding of a pyrimidine-specific regulatory molecule.
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PMID:Integration host factor (IHF) modulates the expression of the pyrimidine-specific promoter of the carAB operons of Escherichia coli K12 and Salmonella typhimurium LT2. 845 62

A total of 79 capsular types have been reported in Klebsiella spp., whereas capsular polysaccharide synthesis (cps) regions were available in only 22 types. Due to the limitations of serotyping, complete repertoire of cps will be helpful for capsular genotyping. We therefore resolved the rest 57 cps and conducted comparative analysis. Clustering results of 1,515 predicted proteins from cps loci categorized proteins which share similarity into homology groups (HGs) revealing that 77 Wzy polymerases were classified into 56 HGs, which indicate the high specificity of wzy between different types. Accordingly, wzy-based capsular genotyping could differentiate capsule types except for those lacking wzy (K29 and K50), those sharing identical wzy (K22 vs. K37); and should be carefully applied in those exhibited high similarity (K12 vs. K41, K2 vs. K13, K74 vs. K80, K79 vs. KN1 and K30 vs. K69). Comparison of CPS structures in several capsular types that shared similarity in their gene contents implies possible functions of glycosyltransferases. Therefore, our results provide complete set of cps in various types of Klebsiella spp., which enable the understandings of relationship between genes and CPS structures and are useful for identification of documented or new capsular types.
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PMID:Genetic analysis of capsular polysaccharide synthesis gene clusters in 79 capsular types of Klebsiella spp. 2649 2