Molecular cloning and sequence analysis of ussurin, a new metalloproteinases/disintegrin from Gloydius ussuriensis / 生物工程学报

The metalloproteinases/disintegrins in the snake venom act as platelet aggregation inhibitor by an antagonism against integrin on platelet through its RGD sequence and may play other important role in cell-cell fusion, cell matrix interaction and other cellular function. Ussurin is a new metalloproteinase/disintegrin that was cloned from Gloydius ussuriensis. Poly (A+) RNA was purified from the total RNA preparation from venom gland of a single G. ussuriensis using the poly (A+) tract-mRNA isolation system. A cDNA library was constructed with the SMART PCR cDNA library construction kit. The cDNA library was screened and the positive clones were selected. The full-length cDNA of Ussurin was obtained. The cDNA encoding the Ussurin precursor has a 51bp 5'-UTR, the open reading frame of Ussurin and a 490 bp 3'-UTR, the open reading frame of Ussurin cDNA nucleotide sequence is 1434 bp and codes for 478 amino acids with a predicted molecular mass of 53.2 kD and an isoelectric point of 5.37. There is no potential N-glycosylation site in the deduced sequence region. Its deduced amino acid sequence consists of four region, a signal sequence of 18 amino acid residues, a zymogen pro-peptide of 171 amino acid residues with a cysteine switch motif (PK-MCGVT) in it, a central metalloproteinase domain of 201 amino acid residues containing a conserved zinc-chelating sequence (HEXXHXXGXXH) and a methionine-turn CIM involving zinc banding also, a space sequence between metalloproteinase domain and disintegrin domain of 15 amino acid residues with a conserved T392, T397, S400, which is specific residues of the P-II snake venom metalloproteinases, a disintegrin domain of 73 amino acid residues with a characteristic RGD region and six-disulfide bonds. Ussurin belongs to P-II class. The cDNA sequence and deduced amino acid sequence of Ussurin precursor were compared with homologous sequence in the GenBank database, the result reveals high degree of homology in sequence and organization pattern of domain with metalloproteinase/disintegrin gene family of other snake species. Compared with the alignment of amino acid sequence of metalloproteinase/disintegrin member, hypervariable regions of this member were revealed, besides they share higher homologous in the zymogen domain. It suggests that the hypervariable regions are the counterparts directly suitable for interacting with different domain of receptors, different receptors or substrates.

Influence of grains or water from KBD endemic area on glycosaminogly can metabolism in Rhesus monkey cartilages / 中国地方病学杂志

Objective　To approach the relationship betwe en glycosaminoglycan metabolism in cartilages and pathogenesis of KBD.Methods　Rhesus monkey was fed with grains and water from KBD endemic area for 18 months to produce the animal model with KBD . The glyc osaminoglycans in the monkey cartilage were extracted by the improved Dish method of Bitter. Purified glycosaminoglycans were digested with chondroitinaseABC, and the enzymatic digests were analyzed by HPLC. Results　Comparing with those of the control, the glycos aminoglycans in the head of femur, tibia plateau and costal cartilage from the Rhesus monkey fed with grains and water from KBD endemic area were undersulfated . Decreased unsaturated 4-sulphated disaccharide (△Di-4S) from the glycosa minoglycans in the head of femur and tibia plateau and decreased unsaturated 6- sulphated disaccharide (△Di-6S) from the glycosaminoglycans in the costal cart ilage were discovered.Conclusions　Detrimental factors in grains and water from KBD endemic area cause undersulfate of the cartilages glycosaminoglycans from Rhesus monkey. The glycosaminoglycans changes have a direct bearing on the patho logical alterations in morphology on the cartilages from the animal model with K BD.