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

The suppression of some envelope proteins, localized in both the periplasm and the outer and inner membranes was shown in phoB and phoM phoR mutants of E. coli. Among these proteins are the proteins of the phosphate regulon and also those not pertaining them. As a result of phoB and phoM phoR mutations, the cytoplasmic membrane was found to be lacking in minor protein of 28,000 Mr, which belongs to the phosphate regulon. Besides, the phoM phoR mutation leads to the loss of protein of 55,000 Mr of the outer membranes, whereas phoB mutation causes loss of protein 37 000 Mr, identified as outer membrane protein OmpT. A damage in the phoB mutant of the protein proteolytic modification, probably determining the suppression of the biosynthesis of E. coli envelope secreted proteins is suggested.
Mol Biol (Mosk)
PMID:[Effect of mutation in phoB and phoM genes for the positive control of alkaline phosphatase biosynthesis on Escherichia coli envelope proteins]. 353 47

pep4 mutants of Saccharomyces cerevisiae accumulate inactive precursors of vacuolar hydrolases. The PEP4 gene was isolated from a genomic DNA library by complementation of the pep4-3 mutation. Deletion analysis localized the complementing activity to a 1.5-kilobase pair EcoRI-XhoI restriction enzyme fragment. This fragment was used to identify an 1,800-nucleotide mRNA capable of directing the synthesis of a 44,000-dalton polypeptide. Southern blot analysis of yeast genomic DNA showed that the PEP4 gene is unique; however, several related sequences exist in yeasts. Tetrad analysis and mitotic recombination experiments localized the PEP4 gene proximal to GAL4 on chromosome XVI. Analysis of the DNA sequence indicated that PEP4 encodes a polypeptide with extensive homology to the aspartyl protease family. A comparison of the PEP4 predicted amino acid sequence with the yeast protease A protein sequence revealed that the two genes are, in fact, identical (see also Ammerer et al., Mol. Cell. Biol. 6:2490-2499, 1986). Based on our observations, we propose a model whereby inactive precursor molecules produced from the PEP4 gene self-activate within the yeast vacuole and subsequently activate other vacuolar hydrolases.
Mol Cell Biol 1986 Jul
PMID:The PEP4 gene encodes an aspartyl protease implicated in the posttranslational regulation of Saccharomyces cerevisiae vacuolar hydrolases. 353 21

Ab initio quantum mechanical calculations have been used to obtain details of the electron density distribution in a high-resolution refined protein structure. It is shown that with accurate atomic co-ordinates, electron density may be calculated with a quality similar to that which can be obtained directly from crystallographic studies of small organic molecules, and that this density contains information relevant to the understanding of catalysis. Atomic co-ordinates from the 1.8 A and 1.5 A resolution refinements of the crystal structure of protease A from Streptomyces griseus have been used to examine the influence of the environment on the electron density in the side-chain of the active site histidine (His57). The neighbouring aspartic acid 102 is the dominant factor in the environment, and quantum mechanical calculations have been performed on these two residues. Most interesting from the point of view of understanding the catalytic process is the effect that Asp102 has on the electron density in the region of the imidazole nitrogen (N epsilon 2) adjacent to the active site serine 195. In the positively charged imidazolium species, there is a polarization of the N epsilon 2-H bond, reducing the bonding density in a manner that may lower the height of the energy barrier for proton transfer. In the uncharged imidazole species, the proximity of Asp102 causes a movement of density from the lone pair region of the N epsilon 2 into the pi bonding region above and below the plane of the ring. Although it is shown that the primary effect of the aspartic acid is electrostatic, this movement is perpendicular to the direction of the electric field inducing it.
J Mol Biol 1985 Apr 20
PMID:Electron density calculations as an extension of protein structure refinement. Streptomyces griseus protease A at 1.5 A resolution. 389 15

In Escherichia coli the iron uptake systems are regulated by the fur gene product. The synthesis of the outer membrane proteins fiu, fepA, fecA, fhuA, fhuE and cir is derepressed at low iron concentrations in the medium or constitutive in a fur mutant. The fur gene region cloned into pACYC184 was analysed by restriction analysis, Tn1000 mutagenesis and complementation studies. The presence of fur+ plasmids repressed synthesis of the proteins fepA, fecA, fhuE and cir in a chromosomal fur mutant. More quantitatively, the repression to wild-type levels was shown with lac fusions to the genes fiu, fepA and cir. In minicells an 18,000 dalton protein was identified as the fur gene product. Correlated with the fur protein a slightly smaller protein, possibly a degradation product, was observed. The gene fur was mapped on the E. coli chromosome near nagA at about 15.5 min.
Mol Gen Genet 1984
PMID:Cloning of the repressor protein gene of iron-regulated systems in Escherichia coli K12. 609 98

A recA::lac operon fusion was constructed using the phage Mu d(Ap, lac) in Escherichia coli to obtain precise measurements of the level of recA gene expression in various genetic backgrounds. The RecA protein normally represents 0.02% of total protein. This value is known to increase dramatically after treatments interrupting DNA synthesis; kinetic experiments showed that the rate of recA expression increases 17-fold within 10 min after UV irradiation or thymine starvation. In mutants affected in SOS regulation or repair the following observations were made: (i) the tif-1 mutation in the recA gene does not alter the basal level of recA expression, suggesting that it improves the protease activity of RecA; (ii) the lexA3 mutation does not create a "super-repressor" of recA; (iii) the tsl-1 mutation in the lexA gene makes the LexA protein a poor repressor of recA at 30 degrees C (2.5-fold derepression) and a poor substrate for RecA protease (3-fold stimulation of recA expression by UV); (iv) the spr-55 amber mutation in the lexA gene causes a 30-fold increase in recA expression, higher than all inducing treatments, and this level cannot be further increased by nalidixic acid; (v) the zab-53 mutation at the recA locus, known to abolish tsl-mediated induction of recA expression, is trans-recessive and thus probably affects a regulatory site on the DNA; (vi) uvrA, B and C, recB and recF mutations do not increase the basal level of recA expression, suggesting that there are not sufficient spontaneous lesions to cause induction even when any one of these three repair pathways is inoperative.
Mol Gen Genet 1982
PMID:Quantitative evaluation of recA gene expression in Escherichia coli. 621 54

The DNA of the promoter region of omp T, including the putative start for the pro-Omp T protein (pro-protein a), has been sequenced. Previous studies showed that trypsin inhibitors prevent the processing of pro-Omp T to Omp T protein which led to the prediction that the processing site would be a lysine or an arginine. The deduced amino acid sequence contains a lysine at amino acid 12 and an arginine at amino acid 17 from the N terminus. Chou-Fassman analysis would predict processing at the lysine (but not the arginine) to remove a 1389 dalton peptide, consistent with the fact that the estimated molecular masses of pro-Omp T and Omp T are 42 kd and 40 kd respectively. In addition, the predicted mRNA of the promoter region can form a stable secondary structure (-17.1 kcal) that sequesters the Shine-Dalgarno (SD) sequence as well as the initiator AUG codon. There is evidence that the per A (tpo, envZ) gene product is required for synthesis of Omp T protein (as well as several outer membrane and periplasmic proteins). The perA gene product could be activating translation of Omp T protein by disrupting the mRNA secondary structure that sequesters the SD sequence. Omp T protein synthesis is reduced at temperatures below 32 degrees C and this may also be related to the greater stability of the sequestered SD sequence of the mRNA at low temperature.
Mol Gen Genet 1984
PMID:Sequence of the regulatory region of omp T, the gene specifying major outer membrane protein a (3b) of Escherichia coli K-12: implications for regulation and processing. 632 18

Src homology 2 domains (SH2) are protein molecules found within a wide variety of cytoplasmic signalling molecules that bind with high affinity to phosphotyrosyl (pY)-containing protein sequences. We report here for crystal structure of the SH2 domain from the adaptor protein SHC (Shc), which has been refined by restrained least-squares methods to an R-factor of 17.3% to 2.7 A. The overall Shc architecture is essentially similar to that determined in other SH2 domains but it shows significant differences in a number of loops, thus providing a molecular surface with no obvious secondary pocket. Based on the knowledge of the crystal structure of the protein a model for a low affinity Shc-bound peptide has been generated from nuclear magnetic resonance data in solution using transferred nuclear Overhauser enhancements as intramolecular distance restraints. The model shows that the tyrosine moiety binds Shc in a rather similar way to that observed for other SH2-peptide complexes, but that the residue in position +3 does not seem to make specific contact with the protein. An intermolecular crystallographic interaction occurs between the pY-binding site and the C-terminal residues of a symmetry-related molecule. This crystal packing interaction suggests how inhibitory regulation could play a role in SHC activity.
J Mol Biol 1995 Nov 17
PMID:Crystal structure of the SH2 domain from the adaptor protein SHC: a model for peptide binding based on X-ray and NMR data. 747 62

Cyanobacteria respond to a decrease in temperature by desaturating fatty acids of membrane lipids to compensate for the decrease in membrane fluidity. Among various desaturation reactions in cyanobacteria, the desaturation of the omega 3 position of fatty acids is the most sensitive to the change in temperature. In the present study, we isolated a gene, designated desB, for the omega 3 desaturase from the cyanobacterium, Synechocystis sp. PCC 6803. The desB gene encodes a protein a 359 amino-acid residues with molecular mass of 41.9 kDa. The desB gene is transcribed as a monocistronic operon that produced a single transcript of 1.4 kb. The level of the desB transcript in cells grown at 22 degrees C was 10 times higher than that in cells grown at 34 degrees C. In order to manipulate the fatty-acid unsaturation of membrane lipids, the desB gene in Synechocystis sp. PCC 6803 was mutated by insertion of a kanamycin-resistance gene cartridge. The resultant mutant was unable to desaturate fatty acids at the omega 3 position. The desA gene, which encodes the delta 12 desaturase of Synechocystis sp. PCC 6803, and the desB gene were introduced into Synechococcus sp. PCC 7942. Whilst the parent cyanobacterium can only desaturate membrane lipids at the delta 9 position of fatty acids, the resultant transformant was able to desaturate fatty acids of membrane lipids at the delta 9, delta 12 and omega 3 positions. These results confirm the function of the desB gene and demonstrate that it is possible to genetically manipulate the fatty-acid unsaturation of membrane lipids in cyanobacteria.
Plant Mol Biol 1994 Oct
PMID:Cloning of omega 3 desaturase from cyanobacteria and its use in altering the degree of membrane-lipid unsaturation. 752 25

During purification of the translation initiation factor IF2 from ompT+ strains of Escherichia coli the IF2 is partially degraded in the presence of membrane debris during the first steps of purification. This is a result of proteolytic cleavage by outer membrane protease OmpT [1]. Here we have investigated the activity of OmpT in 51 clinical E. coli isolates of human origin, by a time dependent OmpT activity assay using IF2 as target protein. The activity of OmpT in the outer cell membrane is highly variable among wild type E.coli strains, ranging from no detectable activity in 65% of the strains to a very high activity in 5 strains (10%). The OmpT activity is closely related to the assay temperature and to the growth temperature of the cells, and can be reduced or even eliminated by lowering the temperature of growth. The results open the possibility of using non-denaturing gel electrophoresis of crude cell lysates as a screening method in population genetic studies of initiation factor IF2 and other cytoplasmic proteins which are cleaved by OmpT.
Biochem Mol Biol Int 1994 Dec
PMID:Protease activity of outer membrane protein OmpT in clinical E.coli isolates--studies using translation initiation factor IF2 as target protein. 769 97

Substrate specificity of two collagenolytic proteases from the king crab Paralithodes camtschatica has been studied. Both proteases are shown to hydrolyze effectively type I and III collagens, gelatin and fibrinogen. The variety of products formed during the enzymatic hydrolysis of the proteins appeared to be different for crab proteases A and C. Studies on peptide hydrolysis demonstrated that protease A cleaves preferably peptide bonds with Arg and Lys as carbonyl components, while protease C prefers hydrophobic amino acids. Kinetic constants of hydrolysis for low molecular weight substrates in the presence of crab proteases have been determined. This allowed us to characterize collagenolytic protease A as a trypsin-like protease. By contrast, collagenolytic protease C was classified as chymotrypsin-like protease although this protease and bovine chymotrypsin are not completely similar. Collagenase substrates Pz-Pro-Leu-Gly-Pro-D-Arg and Z-Gly-Pro-Ala-Gly-Pro-Ala were found to be resistant to both crab proteases.
Comp Biochem Physiol Biochem Mol Biol 1994 Mar
PMID:Substrate specificity of collagenolytic proteases from the king crab Paralithodes camtschatica. 774 10


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