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)

The alanine analogue 1-aminoethylphosphinate [H3C-CH(NH2)-PO2H2] effectively inhibited anthocyanin synthesis in buckwheat hypocotyls and caused an increase in the concentrations of alanine and alanine-derived metabolites. Aminotransferase inhibitors partially alleviated the effects of the analogue. 1-Aminoethylphosphinate did not affect the growth of Klebsiella pneumoniae under anaerobic conditions, but under aerobic conditions it inhibited growth and caused the massive excretion of pyruvate. The analogue inhibited the pyruvate dehydrogenase complex in vitro in the presence of an aminotransferase activity. The transamination product of 1-aminoethylphosphinate, acetylphosphinate (H3C-CO-PO2H2), was found to inhibit the pyruvate dehydrogenase complex in a time-dependent reaction that followed first-order and saturation kinetics and required the presence of thiamin pyrophosphate.
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PMID:Metabolism of 1-aminoethylphosphinate generates acetylphosphinate, a potent inhibitor of pyruvate dehydrogenase. 332 39

The myeloperoxidase (MPO)-mediated decarboxylation of amino acids and the MPO-mediated oxidation of methionine, two potential bactericidal mechanisms, were compared. In the presence of the MPO system (MPO, 50 mU/ml; H(2)O(2), 0.1 mM; Cl(-), 75 mM), 50% of alanine (0.1 mM) was decarboxylated, whereas only 5% of methionine (0.1 mM) was decarboxylated. In contrast, under similar conditions, 80% of methionine was oxidized to methionine sulfoxide. Once methionine was oxidized to methionine sulfoxide, it was decarboxylated (75%) by the MPO system. Methionine at 0.1 mM completely inhibited the decarboxylation of alanine, whereas alanine at a concentration 200 times that of methionine had no effect on the MPO-mediated oxidation of methionine. Sodium azide, an MPO inhibitor, inhibited the decarboxylation of alanine and the oxidation of methionine to the same extent. Tryptophan markedly inhibited the oxidation of methionine, whereas histidine stimulated it. Alanine, glycine, and taurine had no effect. In contrast, all of these amino acids and taurine markedly inhibited the MPO-mediated decarboxylation of alanine. NaN(3), tryptophan, and methionine, which inhibited the MPO-mediated oxidation of methionine, also inhibited the killing of Staphylococcus aureus or Klebsiella pneumoniae by the MPO system; whereas histidine, alanine, and glycine, which did not inhibit the oxidation of methionine, had less or no effect on the killing of these two bacteria by the MPO system. Results suggest that methionine is preferentially oxidized to methionine sulfoxide by the MPO system. Once methionine is oxidized to methionine sulfoxide, it is then readily decarboxylated by the MPO system. The agent responsible for the oxidation of methionine may play an important role in the MPO-mediated killing of bacteria.
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PMID:Myeloperoxidase-mediated oxidation of methionine and amino acid decarboxylation. 628 Nov 85

Although glutamate is a key compound in nitrogen metabolism, little is known about the function or regulation of its two biosynthetic enzymes, glutamate dehydrogenase and glutamate synthase. To begin the characterization of glutamate formation in Salmonella typhimurium, we isolated mutants having altered glutamate dehydrogenase and glutamate synthase activities. Mutants which failed to grow on media with glucose as the carbon source and less than 1 mM (NH(4))(2)SO(4) as the nitrogen source (Asm(-)) had about one-fourth the normal glutamate synthase activity and one-half the glutamine synthetase activity. The asm mutations also prevented growth with alanine, arginine, or proline as nitrogen sources and conferred resistance to methionine sulfoximine. When a mutation (gdh-51) causing the loss of glutamate dehydrogenase activity was transferred into a strain with an asm-102 mutation, the resulting asm-102 gdh-51 mutant had a partial requirement for glutamate. A strain isolated as a complete glutamate auxotroph had a third mutation, in addition to the asm-102 gdh-51 lesions, that further decreased the glutamate synthase activities to 1/20 the normal level. Both the asm-102 and gdh-51 mutations were located on the S. typhimurium linkage map at sites distinct from those found for mutations causing similar phenotypes in Klebsiella aerogenes and Escherichia coli.
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PMID:Salmonella typhimurium mutants with altered glutamate dehydrogenase and glutamate synthase activities. 698 57

The molecular weights, amino acid compositions, amino- and carboxyl-terminal sequences, and ion-exchange peptide maps of the cysteine-containing tryptic peptides were determined for the iron proteins from the nitrogen fixation complexes of Azotobacter vinelandii (Av2) and Klebsiella pneumoniae (Kp2). Our results are compared to the known amino acid sequence of the iron protein from Clostridium pasteurianum (Cp2) [Tanaka, M., Haniu, M., Yasunobu, K. & Mortenson, L. E. (1977) J. Biol. Chem. 252, 7093-7100]. Previous studies have shown the iron proteins to have similar enzymatic functions and spectroscopic properties. Furthermore, the DNAs coding for the iron protein from many different species cross-hybridize [Ruvkun, G. B. & Ausubel, F. M. (1980) Proc. Natl. Acad. Sci. USA 77, 191-195]. Our results indicate that the protein structures are similar yet have significant differences. The amino-terminal sequences of Av2 and Kp2 are extended compared to the amino-terminal methionine of Cp2 and may indicate a different initiation site in these proteins. The aminoterminal sequences for Av2 and Kp2 are more homologous with each other than either of these are with Cp2. The carboxyl-terminal sequences are extended in Av2(14 residues) and Kp2 ( approximately 30 residues) compared to Cp2. The amino- and carboxyl-terminal sequences establish that either the structural gene sizes are different in the three organisms or extensive posttranslational modification must occur in some species. Because cysteinyl residues are involved at the active site of the iron protein, a sensitive peptide mapping technique was used to compare cysteinyl peptides of the iron protein from the three species. Av2 and Kp2 have a redistribution of cysteinyl residues when compared to Cp2. Three important differences in the cysteine distributions were found, namely, residue 4 is valine and residue 148 is alanine in Cp2, but cysteinyl residues occupy these positions in Av2, whereas residue 231 is cysteine in Cp2 but alanine in Av2. The peptide mapping technique provides a method for the investigation of selective chemical modification of cysteinyl residues.
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PMID:Comparison of the iron proteins from the nitrogen fixation complexes of Azotobacter vinelandii, Clostridium pasteurianum, and Klebsiella pneumoniae. 700 44

The susceptibility of Klebsiella aerogenes to cycloserine varied according to the growth conditions. In batch culture, cells were less susceptible to the antibiotic when glycine was present in the medium, presumably due to competition between glycine and cycloserine for the uptake system by which glycine, D-alanine and cycloserine are transported into the cell. In the chemostat at average dilution rates, ammonia-limited cultures were more susceptible to the antibiotic than were glucose-limited cultures. Under phosphate-limiting conditions cultures were at least ten times less susceptible. Under ammonia and phosphate limitation the susceptibility increased with increasing growth rate. The sensitivity of glucose-limited cells was independent of the growth rate. A high-affinity uptake system for cycloserine (as measured by D-alanine transport) was present in ammonia- and glucose-limited cells, but not in phosphate-limited cells. Thus, the phenotypically defined alterations in the susceptibility of the bacterium to cycloserine could be correlated with variations in its uptake system for the antibiotic.
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PMID:Phenotypic variability of the sensitivity to cycloserine of Klebsiella aerogenes NCTC 418, growing in chemostat culture. 703 66

The mannose transporter of E. coli is a member of the phosphotransferase system. It consists of two membrane spanning subunits, IICMan (27.64 kDa) and IIDMan (31.02 kDa) and a peripheral subunit IIABMan (35.02 kDa). It acts by a mechanism that couples vectorial translocation to phosphorylation of the substrate. The subunit ratio determined from densitometric scans of polyacrylamide gels is close to IIABMan2 IICMan1 IIDMan2. A molecular mass of 100 +/- 20 kDa was calculated from electronmicrographs of freeze fractured proteoliposomes containing particles of the IICMan/IIDMan subcomplex with a mean diameter of 6.3 +/- 1.1 nm. This is most compatible with IICMan:IIDMan subunit compositions of 1:2 (89.7 kDa). Fusion proteins between IICMan and IIDMan were generated, with the subunits connected either by a two-residue linker or a 20 residue Ala Pro rich hinge. The fusion proteins had 5%-15% of control phosphotransferase activity. The one with the Ala Pro rich linker could be cleaved with trypsin resulting in a 7 fold increase of activity while the fusion with the two residue linker was resistant to limited trypsinolysis. Taking into account the inside-out orientation of the membrane vesicles the C-terminus of IICMan and the N-terminus of IIDMan are both predicted to be on the cytoplasmic side of the membrane. Two cysteines in IICMan and IIDMan which are conserved in the homologous subunits of the fructose transporter of Bacillus subtilis and of sorbose transporter of Klebsiella pneumoniae are not necessary for phosphotransferase function.
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PMID:The mannose transporter of Escherichia coli K12: oligomeric structure, and function of two conserved cysteines. 781 95

Vitamin B12 production by Gram-negative facultative anaerobic intestinal bacteria, members of the family Enterobacteriaceae, was examined. Klebsiella pneumoniae IFO 13541 was the most effective strain with regard to such production. The growth of the strain and its production of vitamin B12 depended exclusively on the concentration of yeast extract added to the medium. The yeast extract components required for the stimulation of bacterial growth and or vitamin B12 production were identified as aspartic acid and pyrroloquinoline quinone (PQQ) and the relationship between vitamin B12 production and these two components was examined. The metabolism of aspartic acid in this process was also investigated; the major metabolites were alanine, glutaminic acid, and valine. The formation of alanine depended on dehydrogenase, the activity of which was greatly increased with increasing PQQ concentration.
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PMID:Participation of aspartic acid and pyrroloquinoline quinone in vitamin B12 production in Klebsiella pneumoniae IFO 13541. 790 7

A method of randomising specific regions of coding sequences has been devised which utilises the Lac phenotype to identify mutants. Intact genes can be mutagenised, making it unnecessary to reclone the mutations before examining mutant phenotypes. The method has been applied to three residues around the N-terminus of the first alpha helix of the Klebsiella pneumoniae nitrogenase flavodoxin, which are predicted to form part of the phosphate-binding subsite. Surprisingly, most substitutions at Gly12, a highly conserved residue in the chain reversal preceding the alpha helix, appeared to be fairly stable in vivo and were found to retain some function. Substitutions at Lys13, a surface residue which contributes to a patch of positive charge characteristic of the nitrogenase flavodoxins, had no major effect on stability or function. However, most substitutions at Thr14, which is predicted to hydrogen bond to the phosphate of the prosthetic group FMN, were much more destabilising and grossly reduced function. The exceptions were Ala, Cys, Ser and Val, which suggests that the bulk of the residue at this position is critical.
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PMID:Roulette mutagenesis of the FMN-binding site of Klebsiella pneumoniae flavodoxin. 822 78

The genes encoding methylmalonyl-CoA decarboxylase from Veillonella parvula were cloned on plasmids using oligonucleotides derived from N-terminal amino acid sequences as specific probes. The entire DNA sequence of the methylmalonyl-CoA decarboxylase genes together with upstream and downstream regions was determined. The genes encoding subunits alpha (mmdA), delta (mmdD), epsilon (mmdE), gamma (mmdC), and beta (mmdB) of the decarboxylase were clustered on the chromosome in the given order. The previously unnoted epsilon-chain (M(r) 5,888) was clearly shown to be a subunit of the decarboxylase by correspondence of the N-terminal amino acid sequence with that deduced from the DNA sequence of mmdE. The alpha-subunit was 60% identical with the carboxyltransferase domain of rat liver propionyl-CoA carboxylase, the beta-subunit showed 61% sequence identity with the beta-subunit of oxaloacetate decarboxylase from Klebsiella pneumoniae, and the biotin-containing gamma-subunit was 29-39% identical with biotin-domains of other biotin enzymes. The delta-subunit of methylmalonyl-CoA decarboxylase and the gamma-subunit of oxaloacetate decarboxylase did not show significant sequence homology. The gross structure of both proteins, however, was similar, consisting of a hydrophobic membrane anchor near the N terminus, a proline/alanine linker, and a remarkable accumulation of charged amino acids in the C-terminal part. The sequence of the small epsilon-subunit could be aligned to the C-terminal region of the delta-subunit downstream of the proline/alanine linker, where the two subunits were 47% identical. Of considerable interest for the mechanism of Na+ transport are the long stretches of complete sequence identity between the hydrophobic beta-subunits of methylmalonyl-CoA decarboxylase and oxaloacetate decarboxylase and the presence of two conserved aspartic acid residues within putative membrane-spanning helices.
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PMID:Sequence of the sodium ion pump methylmalonyl-CoA decarboxylase from Veillonella parvula. 822 15

The melibiose carrier of Klebsiella pneumoniae couples sugar transport to H+ and Li+, while that of Escherichia coli uses Na+ besides the other two cation species (Hama and Wilson, 1992). We have shown that the K. pneumoniae melibiose carrier is capable of recognizing Na+ when the amino-terminal 81 residues are replaced by the corresponding region of the E. coli melibiose carrier (Hama and Wilson, 1993). In this amino-terminal region there are 5 residues that are not conserved between the two carriers. In this study, we changed each of the 5 residues of the K. pneumoniae carrier to the one in the E. coli carrier. The substitutions are Ile-36-->Val, Val-43-->Leu, Leu-54-->Trp, Ala-58-->Asn, and Cys-68-->Ala. With four of the five mutants, Ile-36-->Val, Val-43-->Leu, Leu-54-->Trp, and Cys-68-->Ala, sugar accumulation was not affected by Na+. In striking contrast, melibiose and methyl-1-thio-beta-D-galactopyranoside accumulation was greatly stimulated by Na+ with the Ala-58-->Asn mutant. Furthermore, Na+ uptake coupled to downhill melibiose transport was observed with the Ala-58-->Asn mutant. These results indicate that the Ala-58-->Asn substitution enables the K. pneumoniae melibiose carrier to couple sugar transport to Na+. It is clear that the Asn-58 residue (Asn-54 in the E. coli carrier) is involved in Na+ recognition.
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PMID:Replacement of alanine 58 by asparagine enables the melibiose carrier of Klebsiella pneumoniae to couple sugar transport to Na+. 828 62


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