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)

The amino acid sequence T-P-P-T-P-S-P-S is tandemly duplicated in the heavy chain of human immunoglobulin A1 (IgA1), the major antibody in secretions. The bacterial pathogen Streptococcus sanguis, a precursor to dental caries and a cause of bacterial endocarditis, yields IgA protease that cleaves only the Pro-Thr peptide bond in the left duplication, while the type 2 IgA proteases of the genital pathogen Neisseria gonorrhoeae and the respiratory pathogen Haemophilus influenzae cleave only the P-T bond in the right half. We have sequenced the entire S. sanguis iga gene cloned into Escherichia coli. A segment consisting of 20 amino acids tandemly repeated 10 times, of unknown function, occurs near the amino-terminal end of the enzyme encoded in E. coli. Identification of a predicted zinc-binding region in the S. sanguis enzyme and the demonstration that mutations in this region result in production of a catalytically inactive protein support the idea that the enzyme is a metalloprotease. The N. gonorrhoeae and H. influenzae enzymes were earlier shown to be serine-type proteases, while the Bacteroides melaninogenicus IgA protease was shown to be a cysteine-type enzyme. The streptococcal IgA protease amino acid sequence has no significant homology with either of the two previously determined IgA protease sequences, that of type 2 N. gonorrhoeae and type 1 H. influenzae. The differences in both structure and mechanism among these functionally analogous enzymes underscore their role in the infectious process and offer some prospect of therapeutic intervention.
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PMID:Analysis of the immunoglobulin A protease gene of Streptococcus sanguis. 198 65

The dipeptide permease (Dpp) of Escherichia coli transports peptides consisting of two or three L-amino acids. The periplasmic dipeptide-binding protein (DBP), encoded by the dppA gene, also serves as a chemoreceptor. We sequenced the dpp locus, which comprises an operon of five genes, dppABCDE. Its organization is the same as the oligopeptide permease (opp) operon of Salmonella typhimurium and the spo0K operon of Bacillus subtilis. The dpp genes are also closely related to the hbpA gene, which encodes a haem-binding lipoprotein, and four other genes in an unlinked operon of unknown function in Haemophilus influenzae. Each Dpp protein has an Opp, Spo0K and H. influenzae homologue. Transcription of the dpp operon initiates 165 bases upstream of the predicted dppA start codon. The start site for transcription is preceded by potential -35 and -10 regions of a sigma 70 promoter. During exponential growth in Luria-Bertani (LB) broth, the level of dpp mRNA increases in two steps, one between A590 0.2 and 0.4 and one between A590 0.7 and 1.0. The 310 nucleotides between dppA and dppB include a RIP (repetitive IHF-binding palindromic) element, whose deletion from a multi-copy plasmid causes fivefold and 10-fold reductions in the levels of upstream and downstream dpp mRNA, respectively.
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PMID:The dipeptide permease of Escherichia coli closely resembles other bacterial transport systems and shows growth-phase-dependent expression. 753 91

The kps locus for polysialic acid capsule expression in Escherichia coli K1 is composed of a central group of biosynthetic neu genes, designated region 2, flanked on either side by region 1 or region 3 kps genes with poorly defined functions. Chromosomal mutagenesis with MudJ and subsequent complementation analysis, maxicell and in vitro protein expression studies, and nucleotide sequencing identified the region 1 gene, kpsE, which encodes a 39-kDa polypeptide. Polarity of the kpsE::lacZ mutation suggests an operonic structure for region 1. KpsE is homologous to putative polysaccharide-translocation components previously identified in Haemophilus influenzae type b and Neisseria meningitidis group B. An open reading frame upstream of kpsE encodes a 35-kDa polypeptide with homology to GutQ, a putative ATP-binding protein of unknown function encoded by gutQ of the glucitol utilization operon. Whether expression of the gutQ homolog as the potential first gene of region 1 is required for polysialic acid synthesis or localization is presently unknown.
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PMID:Cloning, sequencing, expression, and complementation analysis of the Escherichia coli K1 kps region 1 gene, kpsE, and identification of an upstream open reading frame encoding a protein with homology to GutQ. 825 90

Neisseria meningitidis FAM20 has recently been shown to produce two Fe-regulated proteins (FrpA and FrpC) related to the RTX family of cytotoxins. Here we report the cloning and DNA sequence of the locus containing the gene encoding the larger meningococcal RTX protein FrpC. FrpC was highly similar to FrpA throughout much of the predicted protein, with two main differences. Whereas the FrpA protein had 13 copies of the nine-amino-acid repeat units typical of RTX proteins, FrpC had 43 copies. The additional copies in FrpC apparently arose from a threefold tandem amplification of a 600bp DNA fragment encoding the repeats. In addition, the frpC gene lacked good promoter consensus sequences. An open reading frame (ORF1) of unknown function was found immediately upstream of frpC, suggesting the possibility that frpC was cotranscribed with ORF1. A probable promoter was found 300bp upstream of ORF1, and it contained a Fur protein-binding sequence found in the promoters of Fe-regulated Escherichia coli genes. DNA upstream of the ORF1/frpC promoter was homologous to IS1016-like elements surrounding capsulation loci of strains of Haemophilus influenzae. A FrpC-like protein (reactive in immunoblots with monoclonal antibody 9D4; multiple reactive bands of about 200 to 120 kDa) was found in five out of eight meningococcal strains but only in one out of 14 other Neisseria, suggesting that FrpC may participate in the pathogenesis of meningococcal disease.
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PMID:Cloning and nucleotide sequence of frpC, a second gene from Neisseria meningitidis encoding a protein similar to RTX cytotoxins. 841 74

Thymidylate kinase (dTMP kinase; EC 2.7.4.9) catalyzes the phosphorylation of dTMP to form dTDP in both de novo and salvage pathways of dTTP synthesis. The nucleotide sequence of the tmk gene encoding this essential Escherichia coli enzyme is the last one among all the E. coli nucleoside and nucleotide kinase genes which has not yet been reported. By subcloning the 24.0-min region where the tmk gene has been previously mapped from the lambda phage 236 (E9G1) of the Kohara E. coli genomic library (Y. Kohara, K. Akiyama, and K. Isono, Cell 50:495-508, 1987), we precisely located tmk between acpP and holB genes. Here we report the nucleotide sequence of tmk, including the end portion of an upstream open reading frame (ORF 340) of unknown function that may be cotranscribed with the pabC gene. The tmk gene was located clockwise of and just upstream of the holB gene. Our sequencing data allowed the filling in of the unsequenced gap between the acpP and holB genes within the 24-min region of the E. coli chromosome. Identification of this region as the E. coli tmk gene was confirmed by functional complementation of a yeast dTMP kinase temperature-sensitive mutant and by in vitro enzyme assay of the thymidylate kinase activity in cell extracts of E. coli by use of tmk-overproducing plasmids. The deduced amino acid sequence of the E. coli tmk gene showed significant similarity to the sequences of the thymidylate kinases of vertebrates, yeasts, and viruses as well as two uncharacterized proteins of bacteria belonging to Bacillus and Haemophilus species.
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PMID:Escherichia coli thymidylate kinase: molecular cloning, nucleotide sequence, and genetic organization of the corresponding tmk locus. 863 67

A homolog of the meningococcal cps locus region E has been identified in Neisseria gonorrhoeae immediately upstream of the gonococcal region D locus. Region E has no detectable function in capsule biosynthesis in Neisseria meningitidis or in lipopolysaccharide biosynthesis in either organism. The open reading frame is homologous to proteins of unknown function in Escherichia coli and Haemophilus influenzae. Further analysis of the N. meningitidis cps cluster has identified a second copy of region D encoding three additional open reading frames, including homologs of DNA methyltransferases. The organization of the region D and E genes in N. gonorrhoeae and N. meningitidis in relation to the cps genes provides some insight into the evolutionary origin of encapsulation in N. meningitidis.
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PMID:Genes associated with meningococcal capsule complex are also found in Neisseria gonorrhoeae. 865 18

Corynebacterium glutamicum accumulates glycine betaine under conditions of high osmolarity. Previous work revealed the existence of a high-affinity glycine betaine permease which is osmotically regulated. In the present study, the corresponding gene was cloned. The betP gene, encoding the glycine betaine uptake carrier, was isolated by heterologous complementation of mutant strain Escherichia coli MKH13. From sequence analysis it is predicted to encode a protein of 595 amino acids. This protein shares 36% identity with the choline transport system BetT and 28% identity with the carnitine transport system CaiT of E. coli, as well as 38% identity with a protein with an unknown function from Haemophilus influenzae. Analysis of hydropathy indicated a common structure for all four transport proteins. After heterologous expression of betP in E. coli MKH13, the measured Km values for glycine betaine and the cotransported Na+ were similar to those found in C. glutamicum, whereas the modulation of activity by osmotic gradients was shifted to lower osmotic values.
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PMID:Isolation, characterization, and expression of the Corynebacterium glutamicum betP gene, encoding the transport system for the compatible solute glycine betaine. 875 42

The N-terminal sequence of a protein, originally described as an adhesin of Helicobacter pylori, was used in an oligonucleotide-based screening procedure of an H. pylori plasmid library in Escherichia coli. Five independent plasmid clones were isolated, all mapping to the same chromosomal region and encoding the H. pylori catalase. The gene, designated katA, comprises 1,518 nucleotides and encodes a putative protein of 505 amino acids with a predicted Mr of 58,599. A second open reading frame, orf2, encoding a putative 32,715-Da protein of unknown function, follows katA. The transcriptional start site of katA mRNA was determined, but no typical consensus promoter sequence was present. A potential binding site for the Fur protein is located upstream of katA. When introduced into the catalase-deficient E. coli double-mutant UM255, the cloned gene readily complemented E. coli for catalase activity. H. pylori KatA is highly homologous to catalases in both prokaryotes and eukaryotes, with the highest homology being shown to Bordetella pertussis (64.9%), Bacteroides fragilis (59.8%), and Haemophilus influenzae (57.9%) catalases. Transposon insertion mutants were generated in three independent H. pylori strains by TnMax5-mediated transposon shuttle mutagenesis. In contrast to the wild-type strains, no significant catalase-specific enzymatic activity could be detected in the mutant strains, consistent with the fact that no additional katA-homologous gene copies were found in the H. pylori chromosome. No significant difference between wild-type and mutant strains for binding to epithelial cells was apparent, suggesting that KatA is not involved in H. pylori adhesion. The cloning and genetic characterization of katA are essential steps for further investigation of the role of catalase in the defense of H. pylori against oxygen-dependent killing mechanisms by polymorphonuclear granulocytes, a process not well understood for this chronically persisting pathogen.
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PMID:Cloning and genetic characterization of Helicobacter pylori catalase and construction of a catalase-deficient mutant strain. 895 20

We determined a 146 kb contiguous sequence at the 25 degrees-36 degrees region of the Bacillus subtilis chromosome containing the amyE-srfA segment. Among the 113 ORFs identified, 33 are already known. functions were assigned to 38 ORFs by a search of non-redundant protein sequence data banks and those of 16 ORFs were suggested through significant similarity with reported sequences. The amino acid sequences of 13 of the ORfs were similar to proteins of unknown function of Escherichia coli, Haemophilus influenzae and other species. We did not find similarities for 29 ORFs to any known proteins. The 146 kb region is rich in enzymes (35 ORFs) related to the metabolism of low molecular mass compounds and five genes for surfactin production occupy about 26 kb of the region.
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PMID:The 25 degrees-36 degrees region of the Bacillus subtilis chromosome: determination of the sequence of a 146 kb segment and identification of 113 genes. 896 2

The glycerol facilitator is one of the few known examples of bacterial solute transport proteins that catalyse facilitated diffusion across the cytoplasmic membrane. A second protein, glycerol kinase, is involved in entry of external glycerol into cellular metabolism by trapping glycerol in the cytoplasm as sn-glycerol 3-phosphate. Evidence is presented that glycerol transport in Pseudomonas aeruginosa is mediated by a similar transport system. The genes encoding the glycerol facilitator, glpF, and glycerol kinase, glpK, were isolated on a 4.5 kb EcoRI fragment from a chromosomal mini-library by functional complementation of an Escherichia coli glpK mutant after establishing a map of the chromosomal glpFK region with the help of a PCR-amplified glpK segment. The nucleotide sequence revealed that glpF is the promoter-proximal gene of the glpFK operon. The glycerol facilitator and glycerol kinase were identified in a T7 expression system as proteins with apparent molecular masses of 25 and 56 kDa, respectively. The identities of the glycerol facilitator and glycerol kinase amino acid sequences with their counterparts from Escherichia coli were 70 and 81%, respectively; this similarity extended to two homologues in the genome sequence of Haemophilus influenzae. A chromosomal delta glpFK mutant was isolated by gene replacement. This mutant no longer transported glycerol and could no longer utilize it as sole carbon and energy source. Two ORFs, orfX and orfY, encoding a putative regulatory protein and a carbohydrate kinase of unknown function, were located upstream of the glpFK operon.
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PMID:Structure and gene-polypeptide relationships of the region encoding glycerol diffusion facilitator (glpF) and glycerol kinase (glpK) of Pseudomonas aeruginosa. 914 91


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