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)

1. Protein extracts obtained from Salmonella minnesota Re mutant cells by treatment with EDTA/NaC1 solution contain a protein which exhibits high affinity to bacterial lipopolysaccharides. The isolation and partial characterization of this lipopolysaccharide-binding protein is described. 2. The protein was purified from EDTA extracts by a two-step procedure consisting of ion-exchange chromatography on CM-Sephadex and preparative polyacrylamide gel electrophoresis at pH 9.5. The yield of the total purification procedure was around 16%. 3. The resulting protein preparation was homogeneous on the basis of disc gel electrophoresis, dodecylsulfate gel electrophoresis, isoelectric focusing in polyacrylamide gel and immunoelectrophoresis. 4. The isoelectric point of the protein was found to be 10.3 at 4 degrees C. Its molecular weight determined by dodecylsulfate gel electrophoresis is 15000. Its amino acid composition is characterized by the absence of histidine and proline, a low content in tyrosine and high amounts of alanine, lysine, aspartic and glutamic acid residues, or their respective amides. 5. The lipopolysaccharide-protein association was shown to be mainly due to ionic interactions of the basic protein with negatively charged groups (probably phosphate and pyrophosphate groups) of the lipid A moiety. 6. Purified lipopolysaccharide-binding protein is immunogenic in rabbits, thus enabling the preparation of specific antiserum. 7. The protein is located at the surface of Salmonella minnesota Re mutant cells as revealed by antiserum absorption with total bacteria. Ferritin-labelling studies further demonstrated that it is evenly spread over the entire cell surface. 8. Comparative antiserum absorption studies using smooth and rough strains of Salmonella minnesota, Salmonella typhimurium, Escherichia coli, Klebsiella and Shigella revealed the presence of lipopolysaccharide-binding protein (or a serologically cross-reacting antigen) in most of the strains tested. From these results the protein can be considered as a common antigen of Enterobacteriaceae.
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PMID:A lipopolysaccharide-binding cell-surface protein from Salmonella minnesota. Isolation, partial characterization and occurrence in different Enterobacteriaceae. 11 33

Klebsiella pneumoniae Mir M7 is a spontaneous parentless morphology mutant which grows as cocci at pH 7 and as rods at pH 5.8. This strain has been characterized as defective in lateral wall formation (at pH7). Data suggest that the cell wall is mainly made up of poles of the rods (G. Satta, R. Fontana, P. Canepari, and G. Botta, J. Bacteriol. 137:727--734, 1979). In this work the isolation and the biochemical properties of the peptidoglycan of both Mir M7 rods and cocci and a nonconditional rod-shaped Mir M7 revertant (strain Mir A12) are described. The peptidoglycan of Mir M7 (both rods and cocci) and Mir A12 strains carried covalently bound proteins which could be easily removed by pronase treatment in Mir M7 rods and Mir A12 cells, but not in Mir M7 round cells. However, when the sodium dodecyl sulfate-insoluble residues of Mir M7 cocci were pretreated with ethylenediaminetetraacetic acid (EDTA), pronase digestion removed the covalently bound proteins, and pure peptidoglycan was obtained. EDTA treatment of the rigid layer of Mir M7 cocci removed amounts of Mg2+ and Ca2+, which were 10- and 50-fold higher, respectively, than the amount liberated from the rigid layer of Mir M7 rods and Mir A12 cells. Amino acid composition was qualitatively similar in both strains, but Mir M7 cocci contained a higher amount of alanine and glucosamine. Mir M7 cocci contained approximately 50% less peptidoglycan than rods. Under electron microscopy, the rigid layer of the Mir M7 rods and Mir A12 cells appeared to be rod-shaped and their shape remained unchanged after EDTA and pronase treatment. On the contrary, the Mir M7 cocci rigid layer appeared to be round, and after EDTA treatment it collapsed and lost any definite morphology. In spite of these alterations, the peptidoglycan of Mir M7 cocci still appeared able to determine the shape of the cell and protect it from osmotic shock and mechanical damages. The accumluation of divalent cations appeared necessary for the peptidoglycan to acquire sufficient rigidity for shape determination and cell protection. We concluded that the coccal shape in Mir M7 cells is not due to loss of cell wall rigidity but is a consequence of the formation of a round peptidoglycan molecule. The possibility that the alterations found in the Mir M7 cocci rigid layer may reflect natural differences in the biochemical composition of the septa and lateral wall of normally shaped bacteria is discussed.
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PMID:Alterations in peptidoglycan chemical composition associated with rod-to-sphere transition in a conditional mutant of Klebsiella pneumoniae. 11 82

A cell-associated pullulanase (alpha-dextrin 6-glucanohydrolase, EC 3.2.1.41) of an extreme thermophile, Bacillus flavocaldarius KP 1228, was purified to homogeneity. The molecular weight and isoelectric point were estimated to be about 55,000 and 7.0, respectively. The N-terminal sequence was Ala-Try-Tyr-Glu-Gly-Ala-Phe-Phe-Tyr-Gln-Ile-Phe-Pro-Asp-Tyr-Phe-Phe-Tyr- Ala- Gly-. The enzyme was most active at pH 6.3. The activities for 5% pullulan and 5% soluble starch were maximal at 75-80 degrees C and at 80-85 degrees C, respectively. The enzyme was stable up to 90 degrees C for 10 min at pH 6.8. The enzyme had no antigenic determinants shared with pullulanases from the mesophiles Klebsiella pneumoniae and B. acidopullulyticus NCIB 11647. A comparison of amino acid composition demonstrated that the proline content increased greatly in a linear fashion with the rise in thermostability in the order K. pneumoniae----B. acidopullulyticus----B. flavocaldarius enzymes, as found with Bacillus oligo-1,6-glucosidases.
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PMID:A hyperthermostable pullulanase produced by an extreme thermophile, Bacillus flavocaldarius KP 1228, and evidence for the proline theory of increasing protein thermostability. 136 21

Peptides obtained by cleavage of a Rhodococcus rhodochrous K22 nitrilase, which acts on aliphatic nitriles such as acrylonitrile, crotonitrile, and glutaronitrile, have been sequenced. The data allowed the design of oligonucleotide probes which were used to clone a nitrilase encoding gene. Plasmid pNK21, in which 2.05-kb sequence covering the region encoding the nitrilase was was placed under the control of the lac promoter, directed overproduction of enzymatically active nitrilase in response to addition of isopropyl beta-D-thiogalactopyranoside in Escherichia coli. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the cell extract showed that the amount of nitrilase was about 40% of the total soluble proteins, leading to the establishment of a simple purification of the nitrilase. The nucleotide sequence of the nitrilase gene predicts a protein composed of 383 amino acids (M(r) = 42,275), including only one cysteine. The amino acid sequence homology between the Rhodococcus nitrilase and the Klebsiella ozaenae bromoxynil nitrilase [Stalker et al. (1988) J. Biol. Chem. 263, 6310-6314] was 38.3%, and a unique cysteinyl residue (Cys-170) in the former nitrilase was conserved at the corresponding position in the latter nitrilase. Cys-170 of the Rhodococcus nitrilase was replaced by Ala or Ser by site-directed mutagenesis. Both mutations resulted in the complete loss of nitrilase activity, clearly indicating that this cysteinyl residue is essential for the catalytic activity.
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PMID:Primary structure of an aliphatic nitrile-degrading enzyme, aliphatic nitrilase, from Rhodococcus rhodochrous K22 and expression of its gene and identification of its active site residue. 139 Jun 87

Cysteine 319 in the large subunit of Klebsiella aerogenes urease was identified as an essential catalytic residue based on chemical modification studies (Todd, M.J., and Hausinger, R.P. (1991) J. Biol. Chem. 266, 24327-24331). Through site-directed mutagenesis, this cysteine has been changed independently to alanine, serine, aspartate, and tyrosine. None of these mutations (C319A, C319S, C319D, and C319Y, respectively) affected the size or level of synthesis of the urease subunits as monitored by polyacrylamide gel electrophoresis. The wild type enzyme and each of the mutant proteins was purified and their properties were compared. The C319Y protein possessed no detectable activity, while activity was reduced in C319A, C319S, and C319D to 48, 4.5, and 0.03% of wild type levels under normal assay conditions. All of the active mutants had a small increase in Km when compared to the wild type value. The active mutants displayed a greatly reduced sensitivity to inactivation by iodoacetamide in comparison to the wild type enzyme, confirming our previous assignment of the essential cysteine to this residue based on active site peptide mapping. In contrast to the wild type enzyme, inactivation of the mutant proteins was not affected by the presence of the competitive inhibitor phosphate, suggesting that the remaining slow rate of iodoacetamide inactivation is due to modification away from the active site. The pH dependence of urease activity was substantially altered in the active mutants with C319S and C319D showing a pH optimum near 5.2, and C319A near 6.7, compared to the pH 7.75 optimum of wild type urease. These data are consistent with Cys-319 facilitating catalysis at neutral and basic pH values by participating as a general acid.
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PMID:Site-directed mutagenesis of the active site cysteine in Klebsiella aerogenes urease. 140 Mar 17

The amino acid sequences of the NH2 terminus and internal peptide fragments of a Rhodococcus rhodochrous J1 nitrilase were determined to prepare synthetic oligonucleotides as primers for the polymerase chain reaction. A 750-base DNA fragment thus amplified was used as the probe to clone a 5.4-kilobase PstI fragment coding for the whole nitrilase. The nitrilase gene modified in the sequence upstream from the presumed ATG start codon was expressed to approximately 50% of the total soluble protein in Escherichia coli. The predicted amino acid sequence of the nitrilase gene showed similarity to that of the bromoxynil nitrilase from Klebsiella ozaenae. The 5,5'-dithiobis(2-nitrobenzoic acid) modification of the nitrilase from R. rhodochrous J1 resulted in inactivation with the loss of one sulfhydryl group/enzyme subunit. Of 4 cysteine residues in the Rhodococcus nitrilase, only Cys-165 is conserved in the Klebsiella nitrilase. Mutant enzymes containing Ala or Ser instead of Cys-165 did not exhibit nitrilase activity. These findings suggest that Cys-165 plays an essential role in the function of the active site.
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PMID:Nitrilase from Rhodococcus rhodochrous J1. Sequencing and overexpression of the gene and identification of an essential cysteine residue. 140 Mar 90

Endogenous, cysteine-rich antimicrobial peptides known as defensins are prominent components of human, rabbit, and rat neutrophils, yet little is known about their occurrence in other mammalian species. Although we did not detect mature (i.e., processed) defensins in equine neutrophil granules, we found that these granules contained small amounts of other cysteine-rich peptides with antimicrobial activity. One of these, eNAP-1, was purified by a combination of gel permeation and reversed-phase high-performance liquid chromatography from acid extracts prepared from the cytoplasmic granules of equine neutrophils. The molecular mass of eNAP-1 was approximately 7.2 kDa, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. Amino acid analysis revealed that eNAP-1 had an unusually high cysteine content and that it was relatively enriched in alanine, glycine, lysine, and proline residues. The partial (N-terminal) amino acid sequence of eNAP-1 was DVQCGEGHFCHDXQTCCRASQGGXACCPYSQGVCCADQRHCCPVGF. Thirty-six of these residues (78.3%) were identical to those of a recently cloned human neutrophil peptide of unknown function and belonging to the granulin family. Homologous peptides have also been noted in rat bone marrow cells and rat kidney epithelins. We tested the ability of eNAP-1 to kill several equine uterine pathogens. Streptococcus zooepidemicus was killed most effectively, sustaining a greater than 99.8% decrease in CFU per milliliter after a 2-h exposure to 100 micrograms of eNAP-1 per ml (approximately 15 microM). Escherichia coli and Pseudomonas aeruginosa were somewhat less susceptible, manifesting 87.0 and 87.1% mean decreases in CFU per milliliter, respectively, after incubation for 2 h with 200 micrograms of eNAP-1 per ml. Klebsiella pneumoniae numbers were not significantly reduced after exposure to eNAP-1. These antimicrobial properties suggest that eNAP-1 may contribute to phagocyte-mediated host defense against equine infections.
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PMID:Identification of eNAP-1, an antimicrobial peptide from equine neutrophils. 163 74

The sequence Cys184-Ala-Asp-Cys187 in the NifL protein of Klebsiella pneumoniae, for which a role in oxygen sensing and/or metal binding has been proposed, was altered by introducing two mutations, Cys184----Ala and Cys187----Ala, using oligodeoxyribonucleotide-directed mutagenesis. Neither mutation abolished ammonium or oxygen control of nif transcription, although some impairment of function was apparent. The two Cys residues are therefore unlikely to have a direct role in oxygen sensing or metal binding, but probably make some contribution to protein folding or stability.
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PMID:Cys184 and Cys187 of NifL protein of Klebsiella pneumoniae are not absolutely required for inhibition of NifA activity. 187 2

Extracts of the bovine tracheal mucosa have an abundant peptide with potent antimicrobial activity. The 38-amino acid peptide, which we have named tracheal antimicrobial peptide (TAP), was isolated by a sequential use of size-exclusion, ion-exchange, and reverse-phase chromatographic fractionations using antimicrobial activity as a functional assay. The yield was approximately 2 micrograms/g of wet mucosa. The complete peptide sequence was determined by a combination of peptide and cDNA analysis. The amino acid sequence of TAP is H-Asn-Pro-Val-Ser-Cys-Val-Arg-Asn-Lys-Gly-Ile-Cys-Val-Pro-Ile-Arg-Cys-Pr o- Gly-Ser-Met-Lys-Gln-Ile-Gly-Thr-Cys-Val-Gly-Arg-Ala-Val-Lys-Cys-Cys-Arg- Lys-Lys - OH. Mass spectral analysis of the isolated peptide was consistent with this sequence and indicated the participation of six cysteine residues in the formation of intramolecular disulfide bonds. The size, basic charge, and presence of three intramolecular disulfide bonds is similar to, but clearly distinct from, the defensins, a well-characterized class of antimicrobial peptides from mammalian circulating phagocytic cells. The putative TAP precursor is predicted to be relatively small (64 amino acids), and the mature peptide resides at the extreme carboxyl terminus and is bracketed by a short putative propeptide region and an inframe stop codon. The mRNA encoding this peptide is more abundant in the respiratory mucosa than in whole lung tissue. The purified peptide had antibacterial activity in vitro against Escherichia coli, Staphylococcus aureus, Klebsiella pneumonia, and Pseudomonas aeruginosa. In addition, the peptide was active against Candida albicans, indicating a broad spectrum of activity. This peptide appears to be, based on structure and activity, a member of a group of cysteine-rich, cationic, antimicrobial peptides found in animals, insects, and plants. The isolation of TAP from the mammalian respiratory mucosa may provide insight into our understanding of host defense of this vital tissue.
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PMID:Tracheal antimicrobial peptide, a cysteine-rich peptide from mammalian tracheal mucosa: peptide isolation and cloning of a cDNA. 202 43

A mutation, serine 170 to alanine, in the proposed ATP binding site of the activator protein NTRC prevents transcriptional activation at sigma 54-dependent promoters both in vivo and in vitro. The rate of phosphorylation of the mutant protein by NTRB and the stability of mutant NTRC-phosphate were similar to those of wild-type NTRC. The phosphorylated mutant protein shows only a slight decrease in affinity (around 2-fold) for tandem NTRC binding sites in the Klebsiella pneumoniae nifL promoter suggesting that the mutation primarily influences the positive control function of NTRC. Moreover the mutant protein is trans dominant to the wild-type protein with respect to transcriptional activation at both the glnAp2 and nifL promoters. In vitro footprinting experiments reveal that the mutant protein is unable to catalyse isomerisation of closed promoter complexes between sigma 54-RNA polymerase and the nifL promoter to open promoter complexes. However, the mutant protein retains the ability to increase the occupancy of the -24, -12 region by sigma 54-RNA polymerase, forming closed complexes at the nifL promoter, which are not detectable in the absence of NTRC. These data support a model in which the activator influences the formation of closed complexes at the nifL promoter in addition to its role in catalysing open complex formation.
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PMID:Influence of a mutation in the putative nucleotide binding site of the nitrogen regulatory protein NTRC on its positive control function. 204 69


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