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)

Representative isolates of nonmucoid Pseudomonas aeruginosa were studied to investigate the hypothesis that mucinophilic and chemotactic properties in this species act as potential factors in the initial stages of pulmonary colonization in patients with cystic fibrosis (CF). Transmission electron microscopy with a surfactant monolayer technique was used in a novel manner to demonstrate the adhesion of all 10 P. aeruginosa strains examined to porcine gastric mucin and tracheobronchial mucin from a patient with CF. Control experiments showed that Escherichia coli K-12 and single representatives of Proteus mirabilis and Klebsiella aerogenes did not bind to these mucins. The Adler capillary technique, used to measure bacterial chemotactic response, showed that purified CF mucin acted as a chemoattractant for most P. aeruginosa strains, with the exception of the nonmotile mutant M2Fla- and the nonchemotactic mutant WR-5. The ability of the major sugar and amino acid components of mucin to act as chemoattractants was investigated. The degree of chemotaxis was strain specific; optimum chemotaxis was observed toward serine, alanine, glycine, proline, and threonine. No strain showed chemotaxis to N-acetylneuraminic acid, but all strains showed a strain-dependent chemotactic response to the sugars L-fucose, D-galactose, N-acetyl-D-galactosamine, and N-acetyl-D-glucosamine. These results provide new information on the mucinophilic and chemotactic properties of nonmucoid P. aeruginosa and support the hypothesis that these properties could play a role in the initial stages of pulmonary colonization in patients with CF.
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PMID:Mucinophilic and chemotactic properties of Pseudomonas aeruginosa in relation to pulmonary colonization in cystic fibrosis. 211 Dec 80

A model for the domain structure of sigma 54-dependent transcriptional activators, based on sequence data, has been tested by examining the function of truncated and chimaeric proteins. Removal of the N-terminal domain of NtrC abolishes transcriptional activation, indicating that this domain is positively required for activator function. Over-expression of this domain as a separate peptide appears to titrate out the phosphorylating activity of NtrB. Removal of the N-terminal domain of NifA reduces activation 3-4-fold. The residual activity is particularly sensitive to inhibition by NifL, suggesting that the role of the N-terminal domain is to block the action of NifL in derepressing conditions. The C-terminal domain of NtrC showed repressor activity when expressed as a separate peptide. This domain is necessary for activator function even when NtrC binding sites are deleted from promoters. A point mutation in the ATP-binding motif of the NtrC central domain, Ser169 to Ala, also abolished activator function. Exchanging the N-terminal domains of Klebsiella pneumoniae NtrC, NifA and Escherichia coli OmpR, did not produce any hybrid activity, suggesting that N-terminal domains in the native proteins specifically recognize the rest of the molecule.
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PMID:The function of isolated domains and chimaeric proteins constructed from the transcriptional activators NifA and NtrC of Klebsiella pneumoniae. 218 Dec 38

The aroA gene of Klebsiella pneumoniae encoding the shikimate pathway enzyme 5-enolpyruvylshikimate 3-phosphate (EPSP) synthase, which is the target of the herbicide glyphosate, was cloned and sequenced from both the wild-type and the glyphosate-resistant mutant K. pneumoniae K1, which possesses a glyphosate-insensitive EPSP synthase. Both genes were expressed in Escherichia coli and were capable of complementing an auxotrophic aroA mutation. The transformed cells showed increased tolerance to glyphosate due to the overproduction of either the mutant or the wild type EPSP synthase. Nucleotide sequence analysis of the K. pneumoniae aroA gene indicated a protein-coding region of 427 amino acids with a derived Mr for the EPSP synthase of 45,976. Comparison of the two aroA alleles showed a single base change resulting in a substitution of Gly-96 to Ala in the deduced amino acid sequence. By comparison with other known EPSP synthase sequences the mutation was shown to be located in a highly conserved region, indicating that this region is essential for the binding of the herbicide glyphosate.
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PMID:Substitution of Gly-96 to Ala in the 5-enolpyruvylshikimate-3-phosphate synthase of Klebsiella pneumoniae results in a greatly reduced affinity for the herbicide glyphosate. 224 Nov 61

The gene encoding the alpha-subunit of the Na+ pump oxalacetate decarboxylase of Klebsiella pneumoniae was cloned and sequenced. The deduced primary structure of the protein was confirmed by protein sequencing of about 30% of the polypeptide chain. The gene has a GC content of 67% and codes for 596 amino acids. The N-terminal methionine is removed in the mature protein which has a calculated molecular mass of 63,600 daltons. The protein consists of two different domains that are connected by a stretch of amino acid residues susceptible to proteolytic cleavage. Limited proteolysis of the native enzyme with trypsin produced fragments of about 51 kDa and 10.2 kDa, the latter of which started with valine 491 and contained the biotin prosthetic group. Peptide sequencing indicated binding of the biotin prosthetic group to lysine 561, 35 residues from the C terminus. The decarboxylase contains an extended alanine- and proline-rich region (positions 502-532) on the N-terminal side of the 10.2-kDa biotin domain. This sequence includes a total of 16 alanine and 9 proline residues.
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PMID:The sodium ion translocating oxalacetate decarboxylase of Klebsiella pneumoniae. Sequence of the biotin-containing alpha-subunit and relationship to other biotin-containing enzymes. 245 15

Nucleotide changes in the nifH gene of Klebsiella pneumoniae were identified by DNA cloning and sequencing of six selected mutant strains. The strains were UN60, C-640-GC----TGC; UN116, C-67-TC----TTC; UN117, G-688-AG----AAG; UN1041, CG-302-C----CAC; UN1678, GC-713-C----GTC; and UN1795, G-439-AG----AAG. Their corresponding amino acid substitutions were UN60, Arg-214----Cys; UN116, Leu-23----Phe; UN117, Glu-230----Lys; UN1041, Arg-101----His; UN1678, Ala-238----Val; and UN1795, Glu-147----Lys. Results from Western and Northern blots of the mutant strains showed significant reductions in both steady-state levels of the accumulated Fe protein and nifH mRNA during derepression in the presence of serine. The relative specific activities of the nitrogenases in strains UN60, UN1041, and UN1795 were less than 2% of the wild type, whereas those in UN116, UN117, and UN1678 were between 28 and 40% of the wild type during enhanced derepression with serine. The residues of Arg-101 (UN1041), Glu-147 (UN1795), and Arg-214 (UN60) were invariant in sequences of a dozen diazotrophs that have been examined thus far. In UN1041, in which Arg-101 of the Fe protein was replaced by His, the Fe protein had a larger apparent molecular weight than that of the other strains on sodium dodecyl sulfate-gel electrophoresis, as detected with rabbit antiserum raised against the C-terminal peptide of the wild-type Fe protein. The reduced levels of nifH mRNA in point mutant strains suggests that nifH (the gene or gene product) may be involved in self-regulation. mRNA transcripts of different sizes were detected when a nifH-specific probe, CCKp2003, was used in the Northern blot hybridization.
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PMID:Characterization of nifH mutations of Klebsiella pneumoniae. 245 77

The sequences upstream and downstream of the cloned gene for the alpha-subunit of the Na+ pump oxaloacetate decarboxylase of Klebsiella pneumonia were determined. An open reading frame in the upstream region was identified as the gene for the gamma-subunit, and an open reading frame in the downstream region represents the gene for the beta-subunit. The deduced primary structure of the gamma- and beta-subunit was confirmed by protein sequencing of about 37 and 22%, respectively, of each polypeptide chain. The gene for the gamma-subunit has a GC content of 64% and codes for 83 amino acids. The protein is not processed at its amino terminus or at its carboxyl terminus. The gene for the beta-subunit has a GC content of 66% and codes for 327 amino acids. The protein contains a blocked aminoterminal methionine residue. Whether processing occurs at the carboxyl terminus is unknown. Hydropathy calculations defined one transmembrane helix in the amino-terminal part of the gamma-subunit and a hydrophilic carboxyl-terminal part that is certainly not embedded within the lipid bilayer. A proline- and alanine-rich sequence in the carboxyl-terminal part may provide the protein with conformational flexibility. According to hydropathy and acrophilicity calculations, the secondary structure of the beta-subunit may be formed with 5 or 6 intramembrane helical segments.
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PMID:The sodium ion translocating oxaloacetate decarboxylase of Klebsiella pneumoniae. Sequence of the integral membrane-bound subunits beta and gamma. 254 31

The ribitol dehydrogenase gene was cloned from wild-type Klebsiella aerogenes and also from a transducing phage lambda prbt which expresses the rbt operon constitutively. The coding sequence for 249 amino acids is separated from the following D-ribulokinase gene by 31 base pairs containing three stop codons, one of which overlaps the ribosome binding site for D-ribulokinase. Three residues in the amino acid sequence differ from that predicted from the DNA sequence: Asp-212 for Asn-212 is probably a protein sequencing error, but -Ala-Val- for -Ser-Ser- at 146-147 appears to be a 'neutral mutation' that may have arisen during prolonged chemostat selection of a strain that superproduces the enzyme from which the protein sequence was determined.
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PMID:Ribitol dehydrogenase of Klebsiella aerogenes. Sequence of the structural gene. 293 28

The structural gene encoding cyclodextrin-glycosyltransferase of Klebsiella pneumoniae strain M5a1 was cloned; it is expressed both in Escherichia coli and in K. pneumoniae and the gene product is secreted into the extracellular space. Determination of the nucleotide sequence revealed an open reading frame coding for a single polypeptide of 655 amino acid (aa) residues. The enzyme is synthesized as a precursor with an N-terminal signal peptide of 30 aa residues, which is proteolytically processed between two alanine residues during export. The primary structure of CGT bears homology with the sequences of amylases from both prokaryotic and eukaryotic origins.
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PMID:Cyclodextrin-glycosyltransferase from Klebsiella pneumoniae M5a1: cloning, nucleotide sequence and expression. 295

The complete nucleotide sequence of the regulatory operon nifLA of a nitrogen fixer Klebsiella oxytoca NG13 was determined, and the transcriptional start point was assigned by S1 mapping. The nifL protein (a repressor) was coded by an open reading frame of 1,485 bases, corresponding to a protein of 495 amino acids with a calculated molecular weight of 55,242. The open reading frame (1,572 bases) of the nifA protein (an activator), corresponding to a molecular weight of 58,649, was confirmed by in vitro transcription-translation experiments, using the wild type and artificially deleted nifA genes. The initiation codon (ATG) of nifA overlapped the termination codon(TGA) of nifL, sharing the two bases T and G. A conserved DNA contact point [Gln-(X)3-Ala-(X)3-Gly-(X)5-Val] common in many DNA binding proteins was found in the C-terminal region of the nifA sequence. The promoter sequences of nifLA, nifB and nifF in K. oxytoca coincided exactly with those of K. pneumoniae in the consensus regions at -12 and -26, although the overall homology in the promoter regions was 96%. Changes of four amino acids were found between the nifA coding sequences of K. oxytoca and K. pneumoniae.
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PMID:Nucleotide sequence of the nifLA operon of Klebsiella oxytoca NG13 and characterization of the gene products. 302 3

A histidine auxotrophic (hisA) mutant of Klebsiella pneumoniae is phenotypically Nif- when grown with 20 micrograms of histidine ml-1 but Nif+ when supplied with histidine at 100 micrograms ml-1. Reversion to Nif+ at 20 micrograms of histidine ml-1 occurs phenotypically by the addition of 2-thiazolyl-DL-alanine or genetically by mutation in hisG; 2-thiazolyl-DL-alanine inhibits and hisG encodes phosphoribosyl phosphotransferase, the first enzyme of the histidine biosynthetic pathway which consumes ATP. Physiological studies of the hisA mutant JS85 showed that after removal of NH4+ from a culture of the mutant grown with 20 micrograms of histidine ml-1, synthesis of nitrogenase polypeptides occurred at a rate similar to that in the wild type for about 3 h and acetylene reduction activity reached about 10% of the fully derepressed wild-type level. Shortly thereafter the concentration of intracellular adenylates decreased; in particular, ATP fell to about 10% of normal levels. Also, nitrogenase proteins (nifHDK products) and the nifJ gene product stopped being synthesized. These effects were not due to impairment of growth or protein synthesis by histidine starvation. Inhibition of phosphoribosyl phosphotransferase with 2-thiazolyl-DL-alanine restored nitrogenase activity and synthesis, indicating that the effect of the hisA mutation on nif expression was probably a consequence of lowered energy resources that occurred during anaerobic N starvation. The loss of ATP was not associated with nitrogenase synthesis or activity, since hisA nifA and hisA nifH double mutants underwent a loss of ATP in derepressing conditions. Transcription from the nifL, nifN, and nifH promoters was examined in hisA strains with Mu d(Ap lac) fusions in these nif genes. Transcription was not significantly influenced under conditions where adenylates were decreased in concentration. Also nif mRNA apparently accumulated in cultures unable to synthesize nitrogenase, suggesting that translational control of nif gene product synthesis occurs under unfavorable energetic conditions.
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PMID:Regulation of nitrogenase synthesis in histidine auxotrophs of Klebsiella pneumoniae with altered levels of adenylate nucleotides. 327 13


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