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)

A flexible M13 vector library incorporating the BstXI site has been developed. DNA cut by any currently commercially available restriction endonuclease that generates a 4-nucleotide (nt) 3' overhang can be ligated into a specific clone of the library. The BstXI enzyme recognizes a 6-bp bipartite palindromic sequence. The central nucleotides are not specified, and form a 4-base, 3' overhang when cut by BstXI. 5' CCANNNNN NTGG GGTN NNNNNACC 5' Since the 4-base overhang formed is not part of the BstXI recognition sequence, it is possible to generate a library of 256 different clones by introducing the BstXI site, 151 of the possible 256-member library have been isolated, including all 13 M13BF clones in which the overhang formed by BstXI digestion is complementary to those formed by currently available restriction endonucleases. Of these 13 vectors, BstXI digestion of six clones results in nonpalindromic cohesive ends and should facilitate in vitro tandem gene amplification. The BstXI site is adjacent to the four codons corresponding to the factor Xa recognition sequence. Hence the vector library could facilitate the expression of a fusion protein that could be proteolytically cleaved by factor Xa.
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PMID:An M13 vector library for cloning DNA with four nucleotide 3' overhangs. 227 Feb 30

We report a factor VII (FVII) variant, FVIIShinjo, characterized by normal FVII antigen levels and variable procoagulant activity using tissue thromboplastin from different sources. Normal FVII activity is obtained using human placenta thromboplastin but low activity using rabbit or bovine brain thromboplastin. Exons 2-8 and the intron-exon junctions of the FVII genes of the propositus were amplified by PCR from DNA extracted from peripheral white blood cells, and screened by single-strand conformational polymorphism (SSCP) analysis. DNA fragments showing aberrant mobility were cloned and sequenced. We detected a single-point mutation, a homozygous G to A transition at nucleotide position 6,055 in exon 4, which results in the substitution of Arg 79 by Gln in the first EGF-like domain. This mutation results in a loss of a site for the restriction endonuclease MspI. The Msp I digestion pattern of the PCR-amplified exon 3+4 fragments from each member of the family was determined. The Msp I haplotypes were consistent with this G to A transition being associated with reduced FVII activity as detected using thromboplastins from various species. We conclude that the Arg 79 to Gln substitution in the first EGF-like domain of FVII identified in the propositus is responsible for the inherited FVII abnormality in this Japanese family. We postulate that one of the sites of interaction between FVII and tissue thromboplastin includes Arg 79 in the first EGF-like domain of factor VII.
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PMID:Factor VIIShinjo: a dysfunctional factor VII variant homozygous for the substitution Gln for Arg at position 79. 760 84

A gene coding for the Nereis sarcoplasmic calcium-binding protein (NSCP) was synthesized and expressed in Escherichia coli. The sequence of the gene was derived from the protein sequence by reverse translation. It possesses a number of unique, regularly spaced, restriction endonuclease cleavage sites to facilitate future site-directed mutagenesis. For the cloning strategy the gene sequence was divided into four parts. Three parts were cloned by ligation of hybridized oligomers and one part by inverse PCR. The protein was expressed as a fusion protein with the bacterial chloramphenicol acetyl-transferase (CAT), which could be easily purified by affinity chromatography. At the junction of the CAT and NSCP moieties a recognition site for the proteolytic enzyme factor Xa was built in. However, the distance between the moieties appeared to be crucial to warrant cleavage. A kinetic analysis showed that NSCP prepared from the sandworm and the one expressed by E. coli behaved in the same way. This system provides a basis for site-specific mutagenesis studies, in order to elucidate the molecular mechanism of cation binding and concomitant conformational changes.
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PMID:Cloning, expression and purification of a sarcoplasmic calcium-binding protein from the sandworm Nereis diversicolor via a fusion product with chloramphenicol acetyltransferase. 814 89

Resistance to the anticoagulant effects of activated protein C (APC) is now considered the most prevalent cause of inherited thrombophilia. The great majority of patients with activated protein C resistance (APCR) have a missense mutation in the factor V molecule (factor V Leiden, FVR506Q) resulting in defective inactivation of factor Va due to a loss of an APC cleavage site. The diagnosis of APCR has been based upon the inability of APC to prolong the activated partial thromboplastin (aPTT) clotting time in subjects with APCR. However, this assay has a number of deficiencies which limit its general use. We have evaluated a newly described one-stage tissue factor dependent factor V coagulation assay for APCR in 117 patients and controls and compared the results of this assay in a blinded manner to a polymerase chain reaction (PCR) based assay for the molecular defect of factor V Leiden. 43% (50/117) of the patients studied were receiving coumadin or heparin, or had a lupus anticoagulant. The tissue factor dependent factor V assay had 100% specificity and sensitivity for factor V Leiden and successfully predicted a homozygous state in the three documented homozygotes. The PCR-based assay for factor V Leiden resulted in a single false positive assay due to a silent A to C transition at nucleotide 1692 resulting in the loss of the Mnl restriction endonuclease cleavage site. The single-stage tissue factor dependent factor V assay is a highly sensitive and generally applicable assay for APCR.
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PMID:Evaluation of a tissue factor dependent factor V assay to detect factor V Leiden: demonstration of high sensitivity and specificity for a generally applicable assay for activated protein C resistance. 894