Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The remarkable resistance of isolated ribosomes to gelonin is overcome by cofactors present in post-ribosomal supernatants. In rat liver post-ribosomal supernatant RNA is the cofactor responsible of the sensitization of ribosomes. Isolated RNA, which consists mostly of deacylated tRNA, accounts for less than 10 per cent of the activity of the original supernatant. The activity of the supernatant is completely destroyed by micrococcal nuclease and RNAase A and also by proteinase K, suggesting that some protein enhances the effect of RNA. RNA has a role also in the sensitization of ribosomes to alpha-sarcin, an RNAase which inactivates ribosomes by hydrolyzing a single phosphodiester bond in the same region of 28S rRNA which is the target of the N-glycosidase activity of gelonin.
Biochem Mol Biol Int 1994 Mar
PMID:RNA present in post-ribosomal supernatants makes ribosomes susceptible to inactivation by gelonin and alpha-sarcin. 751 79

Monoclonal antibodies were raised against a fusion between the Escherichia coli maltose-binding protein and LciA, the immunity protein that protects Lactococcus lactis against the effects of the bacteriocin lactococcin A. One of the antibodies directed against the LciA moiety of the fusion protein was used to locate the immunity protein in the L. lactis producer cell. LciA was present in the cytosolic, the membrane-associated, and the membrane fractions in roughly equal amounts, irrespective of the production by the cells of lactococcin A. The monoclonal antibody specifically reacted with right-side-out vesicles obtained from a strain producing the immunity protein. It did not react with inside-out vesicles of the same strain, or with right-side-out vesicles obtained from a strain producing both LciA and lactococcin A. Also, externally added lactococcin A blocked the interaction between the antibody and right-side-out vesicles obtained from a strain producing only LciA. The epitope in LciA was localized between amino acid residues 60 and 80. As the epitope could be removed from right-side-out vesicles by proteinase K, it is located at the outside of the cell. The immunity protein contains a putative alpha-amphiphilic helix from residue 29 to 47. A model is proposed in which this helix is thought to traverse the membrane in such a way that the C-terminal part of the protein, containing the epitope, is on the outside of the cell. Vesicle-fusion studies together with leucine-uptake experiments suggest that the immunity protein interacts with the putative receptor for lactococcin A, thus preventing pore formation by the bacteriocin.
Mol Microbiol 1994 Nov
PMID:Mode of action of LciA, the lactococcin A immunity protein. 753 83

We have previously described mutant S. cerevisiae that are defective in peroxisome biogenesis (peb mutants) (Zhang, J. W., Y. Han, and P. B. Lazarow. 1993. J. Cell Biol. 123:1133-1147.). In some mutants, peroxisomes are undetectable. Other mutants contain normal-looking peroxisomes but fail to package subsets of peroxisomal proteins into the organelle (Zhang, J. W., C. Luckey, and P. B. Lazarow. 1993. Mol. Biol. Cell. 4:1351-1359.). In peb1 (pas7) cells, for example, the peroxisomes contain proteins that are targeted by COOH-terminal tripeptides and contain acyl-CoA oxidase (which is probably targeted by internal oligopeptides), but fail to import thiolase (which is targeted by an NH(2)-terminal 16-amino acid sequence). These and other data suggest that there are three branches in the pathway for the import of proteins into peroxisomes, each of which contains a receptor for one type of peroxisomal topogenic information. Here, we report the cloning and characterization of the PEB1 gene, that encodes a 42,320-Da hydrophilic protein with no predicted transmembrane segment. The protein contains six WD repeats, a motif which has been found in 27 proteins involved in diverse cellular functions. The PEB1 gene product was tagged with the hemagglutinin epitope and found to rescue thiolase import in the peb1 null mutant. The epitope-tagged protein was shown to be inside of peroxisomes by immunofluorescence, digitonin permeabilization, equilibrium density centrifugation, immunoelectron microscopy, and proteinase K protection studies. The PEB1 gene product does not cleave the thiolase-targeting sequence. It may function to draw thiolase into peroxisomes.
 ...
PMID:PEB1 (PAS7) in Saccharomyces cerevisiae encodes a hydrophilic, intra-peroxisomal protein that is a member of the WD repeat family and is essential for the import of thiolase into peroxisomes. 753 4

Prions are composed largely, if not entirely, of the scrapie isoform of the prion protein (PrPSc). Conversion of the cellular isoform (PrPC) to PrPSc is accompanied by a diminution in the alpha-helical content and an increase in the beta-sheet structure. To investigate the structural basis of this transition, peptide fragments corresponding to Syrian hamster PrP residues 90 to 145 and 109 to 141, which contain the most conserved residues of the prion protein and the first two putative alpha-helical regions in a PrPC model, were studied using infrared spectroscopy and circular dichroism. The peptides could be induced to form alpha-helical structures in aqueous solutions in the presence of organic solvents, such as trifluoroethanol and hexafluoroisopropanol, or detergents, such as sodium dodecyl sulfate and dodecyl phosphocholine. NaCl at physiological concentration or acetonitrile induced the peptides to acquire substantial beta-sheet. The intermolecular nature of the beta-sheet was evident in the formation of rod-shaped polymers as detected by electron microscopy. Resistance to hydrolysis by proteinase K and epitope mapping argue that the beta-sheet structures were formed by the interaction of residues lying between 109 and 141. A similar range of residues was shown by nuclear magnetic resonance spectroscopy to be capable of forming alpha-helices. The alpha-helical structures seem to require a hydrophobic support from either intermolecular interactions or the hydrophobic environment provided by micelles, in agreement with the predicted hydrophobic nature of the packing surface among the four putative helices of PrPC and the outer surfaces of the first two helices. Our results suggest that perturbation of the packing environment of the highly conserved residues is a possible mechanism for triggering the conversion of PrPC to PrPSc where alpha-helices appear to be converted into beta-sheets.
J Mol Biol 1995 Jul 21
PMID:Conformational transitions in peptides containing two putative alpha-helices of the prion protein. 754 50

2-Chloro-2'-deoxyadenosine (cladribine), an analog of deoxyadenosine, is an important new drug for the treatment of hairy cell leukemia and other forms of adult and pediatric leukemia. By a gel-shift binding assay, we identified an activity in HeLa nuclear extracts that recognizes and binds to oligonucleotides substituted with 2-chloroadenine (ClAde). The activity was specific for ClAde residues because control oligomers did not readily compete out the complex. The binding factor was a monomeric protein that was resistant to inactivation by heating at 45 degrees C but sensitive to heating at 65 degrees C, proteinase K treatment, and 5 mM ZnCl2. This protein, designated ClAde recognition protein (CARP), appeared to be related to a protein that recognized other forms of DNA damage. Gel-shift binding reactions with ultraviolet (UV)-irradiated oligomers revealed a UV-specific protein/DNA complex that had an electrophoretic mobility similar to that of the CARP/DNA complex, and CARP binding to ClAde-containing oligomers was readily competed out by UV-irradiated DNA. Moreover, CARP activity was present in extracts prepared from UV-sensitive xeroderma pigmentosum group A cells but not in a subset of cells from group E, suggesting that CARP was similar to a previously described repair associated factor, xeroderma pigmentosum-E binding factor. Our findings support a possible repair process for ClAde residues incorporated into cellular DNA.
Mol Carcinog 1995 Aug
PMID:A human factor that recognizes DNA substituted with 2-chloroadenine, an antileukemic purine analog. 764 63

The in vivo orientation of the channel forming porin OmpF from the outer membrane of Escherichia coli was assessed by immunological, biochemical and structural techniques. Porin OmpF exists as a trimer of channels formed by 16 antiparallel beta-strands. These are connected by long hydrophilic loops on one side of the bilayer and short loops or beta-turns on the other. The former constitute the rough side of the porin channel, the latter the smooth side. Epitopes at the cell surface have all been mapped within the long loops, suggesting a rough-side-out orientation of OmpF in the membrane. We analyzed detergent solubilized OmpF trimers, reconstituted 2-D OmpF crystals, OmpF containing outer membranes (sacculi) and intact cells of an E. coli strain overexpressing OmpF. Both solubilized OmpF and OmpF containing sacculi were exposed to proteases, and distinct cleavage sites were identified by protein sequencing. Solubilized OmpF, reconstituted 2-D OmpF crystals and detergent extracted sacculi were tested for their capacity to adsorb colicin N. We used antibodies directed against surface exposed epitopes for immunogold labeling of reconstituted 2-D OmpF crystals and sacculi. The surfaces of intact cells and extracted sacculi were analyzed by electron microscopy and image processing. Finally, a full 3-D reconstruction of negatively stained OmpF containing sacculi revealed the OmpF trimer in its native conformation within the outer membrane. Colicin N and antibody experiments, as well as the 3-D map of the sacculi demonstrated that OmpF exposes the long loops to the extracellular space. In contrast, reconstituted crystalline OmpF vesicles and double layered sheets were found to be in an inside-out conformation, hence hiding colicin or antibody binding epitopes. Two proteinase K cleavage sites were identified, one on a protruding loop and the other inside the channel on the loop penetrating the pore.
J Mol Biol 1993 Oct 05
PMID:The orientation of porin OmpF in the outer membrane of Escherichia coli. 769 68

Our interest in detecting genotoxic exposure in earthworms led us to isolate high quality DNA from the Eisenia fetida species. For that, we compared a modification of the conventional phenol-chloroform extraction procedure, usually referred to as the Maniatis procedure, to two commercially available kits reportedly eliminating multiple partitions in phenol and chloroform, namely the Qiagen and Nucleon protocols. From the 260 nm optical density values, the commercial kits extracts hinted toward higher DNA recovery with those procedures. However, the 260/280 nm ratios indicated that the quality of the DNA isolated with the modified Maniatis procedure was purer than that isolated with the commercial kits, the latter being most probably contaminated by proteins and/or RNA. The Maniatis procedure was slightly modified by the introduction of a potassium acetate step for protein precipitation and by shortening the proteinase K treatment from 12-18 h to only 2 h. The higher quality of the DNA isolated by phenol-chloroform extraction was confirmed by quantification with the fluorescent 3,5-diaminobenzoic acid assay. Preliminary results suggest that the modified Maniatis procedure herein described is not only applicable for DNA adducts studies using 32P-postlabelling techniques but is also suitable for DNA extraction from other earthworm species such as Lumbricus terrestris.
Mol Cell Biochem 1995 Jan 12
PMID:Isolation of genomic DNA from the earthworm species Eisenia fetida. 775 38

Gel retardation assays using pea nuclear extracts have detected specific binding to regions of the promoter of the pea plastocyanin gene (petE). Several complexes which differ in sensitivity to competition with unlabelled promoter fragments and various DNA alternating copolymers, to heat treatment and to digestion with proteinase K have been detected. A protein factor, PCF1, forming one of these complexes was heat-stable and most sensitive to competition with poly(dAdT).poly(dAdT) compared to other alternating copolymers. DNase I footprinting assays showed that tracts of A/T-rich sequence within the -444 to -177 positive regulatory region of the petE promoter were protected in the presence of the pea nuclear extract. The factor PCF1 copurified with a high-mobility-group (HMG) protein preparation from pea chromatin. DNase I footprinting with the HMG protein preparation demonstrated that similar tracts of A/T-rich sequences within the promoter were protected. Southwestern-blot analysis of pea HMG proteins purified by gel filtration through Superose 12 detected a single DNA-binding species of 21 kDa. The properties of the factor PCF1 suggest that it is likely to be an HMG I protein.
Plant Mol Biol 1994 Dec
PMID:HMG protein binding to an A/T-rich positive regulatory region of the pea plastocyanin gene promoter. 785 26

Alveolar macrophages of patients with alveolar proteinosis, obtained by lung lavage, contain a large number of intracytoplasmic inclusions with mutlilamellar membranous structures, called fused-membrane structures, having a periodicity of 4.7 nm. To analyze the composition of these structures, we concentrated them from the bronchoalveolar lavage fluid of patients by a combination of sucrose density-gradient ultracentrifugation and enzyme hydrolysis using proteinase K. Fused-membrane structures were most numerous (26.2%) in a fraction obtained at the interface between 1.0 and 1.1 M sucrose solutions separated after proteinase K hydrolysis. This fraction was rich in acidic phospholipids. Hydrophobic surfactant apoproteins constituted about 77% of the proteins in this fraction, and a remarkable increase in the content of surfactant-associated protein C (SP-C) was found. The phospholipid-to-protein ratio was 0.25:1. Based on these results, we tried to reconstitute fused-membrane structures from purified lipids and hydrophobic proteins isolated from the patients' lavage fluid or from pig lungs. Only in the presence of both phospholipids and SP-C were similar multilamellar structures, having a periodicity of 4.3 to 4.5 nm, formed. These results suggest that fused-membrane structures have a close relationship to a hydrophobic surfactant-associated protein, SP-C, which accumulates in alveolar macrophages, possibly by incomplete digestion.
Am J Respir Cell Mol Biol 1995 Feb
PMID:Analysis of fused-membrane structures in bronchoalveolar lavage fluid from patients with alveolar proteinosis. 786 22

This paper describes low-density mucus glycoconjugates released from feline trachea by dirhamnolipid (DRL), a toxin from Pseudomonas aeruginosa. Mucus glycoconjugates in feline tracheas were radiolabeled in vivo with 3H-proline and 14C-glucose. Control mucus and that released by 200 micrograms/ml DRL were dissolved in guanidine hydrochloride buffer (GuHCl) and chromatographed on Sepharose CL-2B. Molecules eluting in the void volume (V0) of the column were isolated by isopycnic density gradient centrifugation in CsCl/GuHCl. All samples gave peaks of radiolabeled and periodic acid/Schiff (PAS)-reactive material at rho = approximately 1.50 and approximately 1.60 g/ml, but DRL-stimulated samples contained low-density material (rho < 1.32 g/ml), also PAS-reactive and radiolabeled. Control secretions incubated with DRL in vitro did not form low-density material. In Triton X-100 (1% vol/vol), a nonionic detergent, low-density material behaved as smaller molecules, running in the partially included volume (Vi) of the column of Sepharose CL-2B, but still in the V0 of Sephacryl S-300. Incubation with chondroitinase ABC, heparinase II and III, and keratanase failed to change its elution profile on S-300, evidence against glycosaminoglycans; but proteolysis with trypsin or proteinase K gave two peaks, peptide fragments near the totally included volume of the column and glycopeptides in V0. The V0 glycopeptides banded between 1.50 and 1.55 g/ml in a CsCl gradient and eluted as a single peak in the Vi of Sephacryl S-400, suggesting a distinct homogeneous glycopeptide, smaller than those from normal mucins. The main 14C-labeled sugars in this glycopeptide were fucose, glucosamine, galactosamine, and galactose, consistent with a mucin. Thus, DRL releases stable but noncovalent complexes containing one or more distinct mucinlike glycoconjugates, probably combined with lipids and peptides. We discuss their possible relevance to airway diseases, including cystic fibrosis.
Am J Respir Cell Mol Biol 1995 Mar
PMID:Mucus glycoconjugate complexes released from feline trachea by a bacterial toxin. 787 96


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>