Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0162871 (abdominal aortic aneurysm)
 8,664 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Known types of pairings between mRNA bases and tRNA nucleosides are shown to be consistent with the notion of a translation space TS constructed such that certain wobble-pairings cannot be used in the same translation system without engendering confusion between keto-final codon twins like AAU(ASN)/AAG(LYS) and between amino-final codon twins like AAC(ASN)/AAA(LYS). When TS is abstractly formalized using Coxeter's face-first three-dimensional projection of a four-dimensional hypercube, the resulting model suggests a specific configurational logic for codon recognition by cognate tRNAs. Although this logic will in general permit codons and anticodons to form matching configurations whose loci are six lines parallel to the axis of a cylinder, confusion of keto-final and amino-final codon twins may result from wobble-pairings whose loci are the two of these lines off the surface of the cylinder.
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PMID:A geometric model for codon recognition logic. 805 66

The mitochondrial DNA of a 41 year old patient with ocular myopathy was explored. We found a deletion of 3540 base pair in about 50% of the mitochondrial genomes associated with a homoplasmic point mutation. The mutation at nucleotide pair 7444 converts stop codon AGA into lysine codon AAA (human mitochondrial genetic code). The synergistic effect between two point mutations has already been described in mitochondrial pathology but this is the first time that an association between a deletion and a point mutation is shown.
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PMID:Association of deletion and homoplasmic point mutation of the mitochondrial DNA in an ocular myopathy. 806 Mar 46

A new apolipoprotein (apo) E variant, apoE5-Frankfurt, was identified in a 43-year-old male with moderate hypercholesterolemia. On isoelectric focusing in an immobilized pH gradient, apoE5-Frankfurt migrated to a position more cathodic than apoE4 (Cys112->Arg). On sodium dodecyl sulfate-gel electrophoresis, its apparent molecular weight could not be distinguished from that of the three common apoE isoforms (E2, E3 and E4). Restriction isotyping with CfoI (HhaI) showed that apoE5-Frankfurt had arginine in positions 112 and 158 of the mature protein, suggesting that the mutation accounting for the additional positive charge had occurred in an epsilon 4 allele. The third and the fourth exon of the apoE gene were amplified using the polymerase chain reaction and analyzed by temperature gradient gel electrophoresis. This suggested that there were two mutations in the fourth exon of the mutant allele. Cloning and sequencing disclosed that, apart from the exchange of arginine for cysteine in position 112, a C to A substitution replaced glutamine (CAA) in position 81 by lysine (AAA).
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PMID:Characterization of the gene for apolipoprotein E5-Frankfurt (Gln81->Lys, Cys112->Arg) by polymerase chain reaction, restriction isotyping, and temperature gradient gel electrophoresis. 812 51

The Xy1R protein positively controls expression from the Pseudomonas putida TOL plasmid sigma 54-dependent Pu and Ps promoters, in response to the presence of aromatic effectors such as m-xylene, m-methylbenzyl alcohol, and p-chlorobenzaldehyde in the culture medium. Xy1R also autoregulates its own synthesis. A mutant Xy1R regulator called Xy1R7 was isolated after nitrosoguanidine mutagenesis of the wild-type gene and phenotypic selection for mutants that had acquired the ability to recognize m-nitrotoluene, a nitroarene that is not an effector for the wild-type regulator. The mutant regulator exhibited a single point mutation that resulted in a change in codon 172 (GAA-->AAA), which should result in a Glu-->Lys change in the polypeptide chain. The effector profile of the mutant regulator was determined by measuring beta-galactosidase from a fusion of the Pu promoter to a promoterless lacZ gene. The results showed that the mutant regulator had acquired the ability to recognize m-nitrotoluene, and retained the wild-type regulator's ability to recognize most of the wild-type effectors. Full transcriptional activation of the Pu promoter by Xy1R7, as with the wild-type Xy1R protein, requires its full modular structure, namely the sigma 54 recognition site, the integration host factor binding site, and the upstream activation sequences. The Xy1R7 regulator did not stimulate transcription from the Ps promoter in response to the presence of its effectors, and autoregulated its own synthesis at low levels.
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PMID:Genetic evidence for activation of the positive transcriptional regulator Xy1R, a member of the NtrC family of regulators, by effector binding. 813 29

Protein adducts are used as markers of chemical exposure. Determination of the clearance rate of these adducts from the blood circulation will provide the time frame for their measurement. Radioactive albumin was prepared biosynthetically by repeated intraperitoneal injections of L-[4,5-3H]lysine to a rat. After an affinity purification, an aliquot of this native [3H-lysine]albumin was adducted with 5 mM acrolein. Both the native albumin (A-treated group) and the albumin-acrolein adduct (AAA-treated group) were intravenously injected to separate groups of rats, and the clearance of radioactivity from the plasma was measured as a function of time. At the end of the experiment (33 h after the injection), radioactivity in the whole plasma, and in homogenates of liver, kidney and spleen and their trichloroacetic acid(TCA)-soluble and -insoluble fractions in both A- and AAA-treated groups, was measured. The results, at the initial 11 h after the injection, showed that the radioactivity was cleared from the circulating plasma more rapidly in the AAA-treated group (32% of the injected radioactivity remained) than the A-treated group (52%). At 33 h after the injection, 22% of the injected radioactivity remained in the plasma in the AAA-treated group as compared to 32% in the A-treated group. The whole homogenates of liver and kidney and their corresponding TCA-soluble fractions showed higher radioactivity in the AAA-treated group as compared to the A-treated group. However, the TCA-insoluble fractions from livers and kidneys of the AAA-treated group showed lower radioactivity as compared to the A-treated group. These results indicated that the albumin-acrolein adduct was removed more rapidly from the circulation than the native albumin, and degraded more rapidly by the liver and kidney. There was no preferential removal or degradation of the adducted albumin by the spleen.
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PMID:Rapid plasma clearance of albumin-acrolein adduct in rats. 814 May 86

Through sequencing of amplified DNA containing the appropriate alpha-globin genes we have identified the base substitution leading to the formation of Hb G-Philadelphia [alpha 68(E17)Asn Lys]. Three subjects (approximately 25% Hb G) had an ACC AAA change at codon 68 of the alpha 2-globin gene; the chromosome with this mutation carried two alpha genes (alpha alpha). Six subjects (approximately 33% Hb G) had an AAC AAG change at the same codon of the alpha 2 alpha 1 hybrid gene on a chromosome with the 3.7 kb deletion (-alpha 3.7). These results indicate two independent mutations which likely occurred in different populations; increase in the level of Hb G is primarily dependent upon the loss of one or more alpha-globin genes.
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PMID:Two different mutations in codon 68 are observed in Hb G-Philadelphia heterozygotes. 817 6

The polymerase chain reaction (PCR) was used to amplify an approximately 1.2 kb DNA fragment encompassing the pre-S/S gene region of HBV DNA from serum of patients with acute hepatitis B virus infection. Nucleotide sequence analysis revealed a number of interesting features in the S gene region. Two Bam HI sites were located at nucleotide positions 557 and 872, respectively, in the S gene. Guanine (G) was found at nucleotide position 903 as part of AGA, the codon for arginine (R) corresponding to amino acid position 122 of the S protein. Adenine (A) was found at nucleotide position 1017 as part of AAA, the codon for lysine (K) corresponding to amino acid position 160 of the S protein. Nucleotide sequence alignment revealed a 97% homology to the corresponding domain of an HBVadw genome (clone pFDW294). Within the second loop of the "a" determinant, two mutations resulting in substitution of serine or threonine with the hydrophobic amino acids, methionine at position 143 and with alanine in place of glycine at position 145, are predicted from the consensus nucleotide sequence of the PCR-derived clones. Subtyping with monoclonal antibodies showed that the HBsAg was of the ayw subtype.
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PMID:Variant of hepatitis B virus isolated in Zimbabwe. 830 23

An electrophoretic variant of the lactate dehydrogenase (LDH)-B(H) subunit was discovered in a patient with diabetes mellitus. His LDH activity in serum was slightly lower than normal and the LDH isozyme pattern showed an abnormal migration indicating an LDH-B subunit variant of the fast type. The LDH containing the variant subunit revealed a decreased heat stability. DNA analysis of the variant allele detected a base substitution, an A to G transition, at codon 6 (AAA-->GAA). The mutation resulted in the replacement of a lysine by a glutamic acid (K6E). The change may cause the heat instability and affect the net charge of the variant subunit, resulting in an electrophoretic LDH-B subunit variant of the fast type.
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PMID:Analysis of a genetic mutation in an electrophoretic variant of the human lactate dehydrogenase-B(H) subunit. 831 53

An inherited fibrinogen variant, fibrinogen Bern I, was isolated from plasma of an asymptomatic woman. Routine coagulation studies showed prolonged thrombin and reptilase clotting times. Fibrinogen concentration was diminished when determined by a functional assay, but was normal by the heat precipitation method. The release of fibrinopeptides A and B was not delayed. Two-dimensional gel electrophoresis of mercaptolyzed fragments D of fibrinogen, obtained by digestion with plasmin, showed an abnormal electrophoretic mobility in the gamma-chain remnants of fragments D1 and D2 from fibrinogen Bern I, whereas conversion of D2 to D3 by plasmin resulted in the loss of the abnormal charge, suggesting that the structural abnormality in this variant is located in the region gamma 303 through 356. The molecular defect in fibrinogen Bern I was identified by sequence analysis of genomic DNA amplified by polymerase chain reaction and cloned in M13mp19. The triplet AAC coding for asparagine at position gamma 337 was found to be substituted by AAA coding for lysine. We conclude that the substitution gamma 337 Asn-->Lys in fibrinogen Bern I is responsible for defective polymerization of fibrin monomers and for impaired protection by calcium against plasmic degradation.
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PMID:Fibrinogen Bern I: substitution gamma 337 Asn-->Lys is responsible for defective fibrin monomer polymerization. 840 Feb 60

Sequence analysis of the tyrosinase coding region from an individual with tyrosinase-negative oculocutaneous albinism revealed that the patient was a compound heterozygote. One allele carried a C--> A single-base substitution in codon 355 of exon 3, and the other carried a two-nucleotide deletion in exon 1. The nucleotide substitution caused a putative amino acid change from threonine (ACA) to lysine (AAA), abolishing a signal for N-glycosylation. The two base-pair deletion caused a frameshift, creating a putative premature termination signal at codon 226. The melanocytes from the proband and her affected brother were amelanotic and devoid of measurable tyrosinase activity. Moreover, gel electrophoretic analysis of the immunoprecipitated proband tyrosinase showed that the protein was not processed to the mature glycosylated form, confirming the predicted consequence of the amino acid change. The two-base deletion on the homologous allele was detected only by sequencing genomic DNA. The transcript of this allele was not represented in the cDNA library and could not be detected by PCR mRNA, and the putative truncated protein (approximately 25 kDa) was not present in immunoprecipitates, suggesting that the allele with the missense mutation may be preferentially expressed.
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PMID:Molecular analyses of a tyrosinase-negative albino family. 843 Jul 1


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