Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0519030 (Klebsiella)
 21,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The nifL gene product of Klebsiella pneumoniae inhibits the activity of the positive activator protein NifA in response to increased levels either of fixed nitrogen or of oxygen in the medium. In order to demonstrate that the responses to these two effectors are discrete we have subjected nifL to hydroxylamine mutagenesis and isolated nifL mutants that are impaired in their ability to respond to oxygen but not to fixed nitrogen. Two such mutations were sequenced and shown to be single base pair changes located in different parts of nifL. The amino acid sequence of NifL shows limited homology to the histidine protein kinases which comprise the sensing component of bacterial two-component regulatory systems. In the light of the location of one of the oxygen-insensitive mutations (Leu294Phe) we have reassessed this homology and we suggest that the Gln273-Leu317 region of NifL may facilitate interactions between NifL and NifA.
 ...
PMID:Characterisation of mutations in the Klebsiella pneumoniae nitrogen fixation regulatory gene nifL which impair oxygen regulation. 848 Oct 91

An approximately 70-kDa protein in the culture supernatant of a human pathogenic strain of Klebsiella pneumoniae was labeled in the presence of [32P-adenylate]NAD. Labeling was significantly increased by the addition of dithiothreitol ( > 1 mM) but prevented by treatment of the culture supernatant for 3 min at 56 degrees C. The addition of unlabeled NAD, but not of ADP-ribose, blocked labeling of the approximately 70-kDa protein. The radioactive label was released by formic acid but not by HgCl2 (1 mM) or neutral hydroxylamine (0.5 M). The addition of homogenates of human platelets, human neutrophils, rat brain, rat lung, or rat spleen tissues to the culture supernatant did not induce labeling of eukaryotic proteins. The data indicate that the K. pneumoniae strain produces ADP-ribosyltransferase which modifies an endogenous protein.
 ...
PMID:ADP-ribosylation of an approximately 70-kilodalton protein of Klebsiella pneumoniae. 861 83

During aerobic growth of Klebsiella pneumoniae on malonate, a soluble malonate decarboxylase is induced. Malonate decarboxylation consumes a proton (not H2O) and forms acetate and CO2 (not HCO3-) as products. The enzyme was purified 56-fold to apparent homogeneity. It has a native molecular mass of 142 kDa and consists of four subunits alpha, beta, gamma and delta with molecular masses of 65, 34, 30, and 12 kDa, respectively. Two different forms of the enzyme were recognised: a catalytically inactive SH-enzyme and the catalytically active acetyl-S-enzyme which is formed by post-translational acetylation of the SH-enzyme with ATP, acetate and a specific ligase. The acetyl-S-enzyme was converted into the SH-enzyme by incubation with hydroxylamine or dithioerythritol. Chemical reacylation of the SH-enzyme, which restores catalytic activity, was achieved with acetic anhydride or more efficiently with malonyl-CoA. This acylation of the SH group was prevented after incubation with various thiol-specific reagents. After incubation of the SH-enzyme with iodo[1-14C]acetate, the delta subunit became specifically labelled. This subunit was also labelled after incubation of the acetyl-S-enzyme with [2-14C]malonate. The radioactivity was completely liberated from the protein upon malonate addition. These results indicate that the delta subunit is the acyl-carrier protein of the complex and that malonate decarboxylation proceeds in two steps: the acetyl residue on the ACP is first replaced by a malonyl residue which subsequently undergoes decarboxylation thereby regenerating the acetyl-S-ACP. The binding site for the acyl residues on the acyl-carrier protein was shown to be 2'-(5"-phosphoribosyl)-3'-dephospho-CoA after alkaline cleavage of this prosthetic group from the enzyme and chromatographic as well as mass spectroscopic analyses.
 ...
PMID:Malonate decarboxylase of Klebsiella pneumoniae catalyses the turnover of acetyl and malonyl thioester residues on a coenzyme-A-like prosthetic group. 862 Aug 76

Malonate decarboxylase of Malonomonas rubra is composed of soluble and membrane-bound components and contains an acetyl residue that is essential for catalytic activity. Upon incubation with hydroxylamine, the acetyl residue is removed, forming an inactive thiol enzyme, which is reactivated by acetylation with ATP, acetate, and a specific ligase. After incubation of the thiol enzyme with iodoacetate in the presence of excess dithioerythritol, the prosthetic group thiol residue was carboxymethylated and reactivation by acetylation was impaired. Radioactive labeling with [1-14C] iodoacetate revealed the site of carboxymethyation on a distinct cytoplasmic protein with the apparent molecular mass of 14 000 Da. The same protein was specifically labeled by enzymic acetylation of the thiol enzyme with [1-14C]acetate and ATP. Malonate decarboxlyation by [14C]acetyl malonate decarboxlyation resulted in the release of the radioactive acetyl residue from the enzyme,indicating that this acetyl residue is exchanged for a malonyl residue during catalysis. The acyl carrier protein has been purified as its [14C]carboxymethylated derivative to apparent homogeneity. The prosthetic group of the acyl carrier protein was isolated after alkaline hydrolysis, and its chemical structure was identified by high-performance liquid chromatography (HPLC) with the corresponding compound from citrate lyase from Klebsiella pneumoniae as reference and by mass spectrometry. Malonate decarboxylase was found to carry the same prosthetic group as citrate lyase, i.e. 2'-(5"-phosphoribosyl)-3'-dephospho-CoA.
 ...
PMID:The acyl carrier protein of malonate decarboxylase of Malonomonas rubra contains 2'-(5"-phosphoribosyl)-3'-dephosphocoenzyme A as a prosthetic group. 866 58

The fractional composition of the vaccine preparation obtained by the hydroxylamine treatment of K. pneumoniae 204 cells was studied with the use of gel chromatography in sepharose CL-6B. The preparation was shown to form 2 peaks, only the first high molecular peak being serologically active. The method for the treatment of the culture, obtained directly from a fermenter and stored in a frozen state before treatment, was proposed. In the technology of the manufacture of Klebsiella vaccine preparation the possibility of replacing dialysis with gel chromatography was shown.
 ...
PMID:[The fractional composition of hydroxylamine preparations and of the lipopolysaccharide of a vaccinal strain of Klebsiella pneumoniae]. 930 37

Here, the draft genome of simultaneous nitrification-denitrification strain (SND) Klebsiella sp. KSND revealed possible existence of genes involved in N-assimilation and -dissimilation pathways. The change levels of genes under defined N-sources were analyzed by Quantitative Real-Time PCR. It suggested that NH4+-assimilation via NADP-glutamate dehydrogenase pathway would occur preferentially. NirBD genes were tightly regulated in a lower level, so that nitrite was rapidly consumed for detoxication by denitrification. Three types of nitrate reductase homologues are surprisingly present in KSND, whereas the dominant nitrate reduction for assimilation and denitrification processes mediates by NapA-type nitrate reductase. Nitric oxide reductase homologues FlRd and FlRd-red provide an adequate capacity for NO detoxification. The recombinant hydroxylamine reductase showed high activity in hydroxylamine to generate ammonium, which might contribute to detoxification mechanism in nitrogen cycling. Overall, this study firstly provides valuable insights into the genes expression and enzyme action, which helps understanding the mechanism of SND processes.
 ...
PMID:New insight into the nitrogen metabolism of simultaneous heterotrophic nitrification-aerobic denitrification bacterium in mRNA expression. 3085 40


<< Previous 1 2