Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mitochondrial DNA segments of two independently isolated rho- clones of S. cerevisiae carrying a genetic marker for a threonine tRNA have been characterized by restriction endonuclease analysis and DNA sequencing. The DNA sequences of the two segments have been used to deduce the primary and secondary structures of the tRNA. The threonine tRNA is unusual in having a leucine anticodon (3'-GAU-5'). Despite the anomalous anticodon, the tRNA is proposed to function in mitochondrial protein synthesis. One of the rho- clones contains an additional coding sequence that has been identified as a valine tRNA genes have been located on the wild-type physical map and determined to be transcribed from two different strands.
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PMID:Assembly of the mitochondrial membrane system: sequences of yeast mitochondrial valine and an unusual threonine tRNA gene. 38 33

Familial amyloidotic polyneuropathy (FAP) is a dominantly inherited form of amyloidosis usually associated with an abnormal transthyretin (TTR), previously known as prealbumin. Several disease-related variants of the protein, each with a different amino acid substitution and correlating DNA point mutation, have been identified. The TTR gene from a patient suffering from this disorder was asymmetrically amplified and directly sequenced, revealing a cytosine for thymine substitution in the second base of codon 30 and the creation of a novel Cfo I restriction endonuclease site in exon 2. This mutation results in a previously undescribed substitution of an alanine for valine in the final TTR protein. Analysis of the amino acid mutation reveals it to be a hydrophilic substitution at a hydrophobic core position. Alanine at position 30 represents the second FAP-associated mutation at position 30 in TTR.
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PMID:Familial amyloidotic polyneuropathy: a new transthyretin position 30 mutation (alanine for valine) in a family of German descent. 154 14

Type I familial amyloid polyneuropathy (FAP) is an autosomal dominant hereditary generalized amyloidosis characterized by polyneuropathy and autonomic nerve failure. The main component of the amyloid fibril protein in this disorder has been shown to be a variant prealbumin with a single substitution of a methionine residue for valine at position 30. In the present study we have investigated 19 patients with FAP aged 31 to 67 and an asymptomatic family member using gene analysis with primer-directed enzymatic amplification (PCR) of DNA, isolation of plasma variant prealbumin and immunohistochemical identification of tissue amyloid protein. All patients and a symptom-free boy in the affected family had the mutant prealbumin gene showing abnormal DNA fragments by treatment with restriction endonuclease Bal I, and plasma variant prealbumin was also detected in all of them by reverse-phase high performance liquid chromatography. Rectum biopsies obtained from 9 patients showed amyloid deposits which were specifically immunostained by anti-human prealbumin antiserum. However, an asymptomatic carrier at the age of 16 showed no rectal amyloid deposition. Recent studies of FAP have disclosed that the expression of type I FAP is closely associated with the gene mutation of prealbumin. Accordingly, a simple and rapid method to detect this gene abnormality using PCR technique is considered to be very useful for diagnosis of type I FAP and can also provide valuable information for the genetic counselling of the family members at risk.
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PMID:[Diagnosis of familial amyloid polyneuropathy--gene analysis with primer-directed enzymatic amplification of DNA, isolation of plasma variant prealbumin and immunohistochemical identification of tissue amyloid protein]. 165 25

K99 fimbriae of enterotoxigenic Escherichia coli consist of eight different subunits. A major subunit called fimbrillin forms fimbrial structure and a minor subunit called adhesin localizes at the tip of fimbriae and recognizes host receptor ganglioside. Within this eight gene cluster, fanE and fanF have not yet been sequenced. In this study, fanE and fanF genes were sequenced by analyzing several DNA fragments produced by endonuclease or exonuclease digestion. The fanE gene encoded 227 amino acids containing 20 amino acids of signal peptide starting from GTG (valine) and showed a homology to fanA-fanB. The fanF gene encoded 271 amino acids containing 20 amino acids of signal peptide starting from ATG (methionine) and showed homologies to the fanD gene, fimbrillin gene of F41, adhesin gene of P fimbriae (papG) and adhesin gene of Type 1 fimbriae (fimH). E and F subunits had fifteen and fourteen hydrophobic domains, respectively, which periodically appeared possibly forming a hydrophobic region.
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PMID:The nucleotide sequence of the genes, fanE and fanF of Escherichia coli K99 fimbriae. 168 13

Two leucine-binding proteins with overlapping specificities for the branched-chain amino acids are present in Escherichia coli. In order to study the basis of specificity for the very similar hydrophobic ligands, we have constructed a series of site-directed mutants of both proteins based on inspection of the leucine-isoleucine-valine-binding protein crystal structure reported by Sack et al. (Sack, J. S., Saper, M. A., and Quiocho, F. A. (1989) J. Mol. Biol. 206, 171-191). Each of the mutant proteins was overexpressed and purified, and their binding activity for a wide variety of potential ligands was measured. By introducing a common restriction endonuclease cleavage site in the two proteins, two hybrid binding proteins consisting of the amino-terminal third of one binding protein fused to the carboxyl-terminal two-thirds of the other were created. The results of these studies indicated that the binding site of the leucine-isoleucine-valine binding protein can accommodate a branch at the beta-carbon of the ligand and that hydrophilic groups on the ligand can be accommodated only in certain orientations. None of the single amino acid substitutions resulted in complete switches in specificity between the two proteins, suggesting that additional residues are involved in leucine binding and discrimination among the branched-chain amino acid substrates.
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PMID:Altering the binding activity and specificity of the leucine binding proteins of Escherichia coli. 200 77

Albright's hereditary osteodystrophy is an autosomal dominant disorder characterized by a short stature, brachydactyly, subcutaneous ossifications, and reduced expression or function of the alpha subunit of the stimulatory G protein (Gs alpha) of adenylate cyclase, which is necessary for the action of parathyroid and other hormones that use cyclic AMP as an intracellular second messenger. We identified a unique Gs alpha protein in erythrocytes from two related patients with Albright's hereditary osteodystrophy and reduced Gs alpha bioactivity. The Gs alpha variant was recognized by a carboxyl terminal-specific Gs alpha antiserum but not by polyclonal antiserums specific for the amino terminus of Gs alpha. To investigate the molecular basis for this structurally abnormal Gs alpha protein, we studied the Gs alpha gene by restriction-endonuclease analysis. DNA from the two patients had an abnormal restriction-fragment pattern when digested with Ncol, which was consistent with loss of an Ncol restriction site in exon 1 of one Gs alpha allele. Amplification of a 260-base-pair region that includes exon 1 of the Gs alpha gene and direct sequencing of the amplified DNA revealed an A-to-G transition at position +1 in one Gs alpha allele from each of the two patients. This mutation converts the initiator ATG (methionine) codon to GTG (valine), blocking initiation of translation at the normal site. Translation of the abnormal Gs alpha messenger RNA would result in the synthesis of a truncated Gs alpha molecule lacking the amino terminus. We conclude that in at least some patients with Albright's hereditary osteodystrophy, the disease is caused by a single-base substitution in the Gs alpha gene and is thus due to an inherited mutation in a human G protein.
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PMID:Mutation in the gene encoding the stimulatory G protein of adenylate cyclase in Albright's hereditary osteodystrophy. 210 29

We have isolated and characterized by restriction endonuclease mapping, transcription pattern, and DNA sequencing a beta-tubulin gene from the coenocytic freshwater protoctist, Achlya klebsiana. The gene is intronless and has a single open reading frame that encodes a 444-amino acid residue polypeptide of Mr 49,856. The protein shows a high degree of homology to other beta-tubulins, 85% identity to human beta-tubulin and 89% identity to beta-tubulin of the sporozoan (also a protoctist) Plasmodium falciparum. Fungal beta-tubulins are among the least identical to A. klebsiana beta-tubulin. Through Southern blot hybridization analysis, we determined that there is just one form of beta-tubulin gene in A. klebsiana. Transcription of the gene was studied during sporogenesis. Following induction of sporogenesis, the level of the mRNA increased markedly at 2 h and declined in the next 2 h when mitosis, cytokinesis, and spore development occurred. At the same time, beta-tubulin content increased about 6-fold in the cells. Sporulation in A. klebsiana is not inhibited by antimitotic drugs such as benomyl, colcemid, and colchicine. Benomyl resistance in Neurospora crassa and Aspergillus nidulans has been genetically and molecularly linked to single amino acid substitutions at positions 167 and 165, respectively. The change from phenylalanine to tyrosine conferring benomyl resistance to N. crassa is seen in A. klebsiana, but the valine substitution for alanine in A. nidulans is marked by cysteine replacement in A. klebsiana. The amino acid found at position 165 is not conserved in various beta-tubulins, but phenylalanine at position 167 is extremely conserved.
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PMID:Cloning and analysis of beta-tubulin gene from a protoctist. 239 20

Nonclassic steroid 21-hydroxylase deficiency is a frequent, relatively mild disorder of cortisol biosynthesis characterized by variable signs of postnatal androgen excess. It is inherited as an allelic variant of the CYP21B gene encoding the 21-hydroxylase enzyme. CYP21B is located in the HLA histocompatibility complex, and a nonclassic allele is often associated with characteristic HLA antigens: B14;DR1. A CYP21B gene from a HLA-B14;DR1 homozygous patient with nonclassic 21-hydroxylase deficiency was cloned and analyzed. Five deviations from the normal sequence of CYP21B were found, but only one appeared likely to affect the functional integrity of the protein: codon 281, GTG, encoding valine, was changed to TTG, leucine. An oligonucleotide probe was constructed corresponding to the mutant sequence surrounding codon 281 and hybridized with DNA samples digested with restriction endonuclease Taq I. Samples from 8 nonclassic 21-hydroxylase deficiency patients carrying HLA-B14;DR1 contained a hybridizing fragment 3700 base-pairs long, indicating presence of the val-281 mutation in the CYP21B gene. In contrast, unaffected individuals and one patient who lacked HLA-B14;DR1 showed no evidence of the val-281 mutation in CYP21B. We conclude that the codon 281 mutation is a consistent molecular genetic marker for nonclassic 21-hydroxylase deficiency associated with HLA-B14;DR1.
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PMID:Clinical and genetic characterization of nonclassic 21-hydroxylase deficiency. 278 81

Serum prealbumin variant with a substitution of methionine (Met) for valine (Val) at position 30 is known to be related to Andrade type familial amyloid polyneuropathy (FAP). Recently, the diagnosis of FAP by recombinant DNA techniques has been established. The DNA diagnosis is based on the fact that a nucleotide substitution responsible for Val-Met change results in formation of new restriction sites for Nsi 1 and Bal 1. We conducted the DNA diagnosis studies of 30 constituents of FAP pedigrees originated from Nagano and Hiroshima Prefectures, and compared the results with clinical features. Clinical features of the patients originated from Ogawa Village area in Nagano Prefecture and from Hiroshima Prefecture showed Andrade type FAP such as polyneuropathy and autonomic nervous disorders. Those of the patients from Iiyama City in Nagano Prefecture showed central nervous involvement such as cerebellar ataxia and/or pyramidal tract signs in addition to the clinical features of Andrade type FAP (Iiyama type). DNA prepared from white blood cells was digested with restriction endonuclease Nsi 1 or Bal 1 and subjected to Southern blot hybridization. The resulting DNA segments were fractionated by agarose gel electrophoresis. The gel was alkalized to convert the double-strand DNA to a single-strand form, which then was absorbed on a nylon membrane filter. The prealbumin cDNA was labelled with 32P as a probe. The probe was hybridized with DNA segments on a filter. The filter was placed on the X-ray film to obtain the autoradiogram.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Diagnosis by recombinant DNA techniques and clinical features of familial amyloid polyneuropathy]. 285 18

Nonclassic steroid 21-hydroxylase deficiency is a frequent, relatively mild disorder of cortisol biosynthesis, characterized by variable signs of postnatal androgen excess. It is inherited as an allelic variant of the gene designated CYP21B, which encodes 21-hydroxylase. CYP21B is located in the HLA histocompatibility complex, and a "nonclassic" allelic variant is often associated with characteristic HLA antigens--B14,DR1. We cloned and analyzed the CYP21B gene from a patient homozygous for HLA-B14,DR1 who had nonclassic 21-hydroxylase deficiency. Five deviations from the normal genetic sequence of CYP21B were found, but only one appeared likely to affect the functional integrity of the protein: codon 281, GTG, encoding valine, was changed to TTG, leucine. We constructed an oligonucleotide probe corresponding to the mutant DNA sequence surrounding codon 281 and hybridized the probe with DNA samples digested with the restriction endonuclease Taql. Samples from eight patients with nonclassic 21-hydroxylase deficiency who had the haplotype HLA-B14,DR1 contained a hybridizing fragment 3700 base pairs long, indicating the presence of the valine-281 mutation in the CYP21B gene. In contrast, unaffected subjects and one patient with nonclassic deficiency who did not have HLA-B14,DR1 had no evidence of this mutation. We conclude that the mutation in codon 281 is a consistent molecular genetic marker for nonclassic 21-hydroxylase deficiency associated with HLA-B14,DR1.
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PMID:Molecular genetic analysis of nonclassic steroid 21-hydroxylase deficiency associated with HLA-B14,DR1. 326 7


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