Heparinase III (HepIII) is a 73-kDa polysaccharide lyase (PL) that degrades the heparan sulfate (HS) polysaccharides at sulfate-rare regions, which are important co-factors for a vast array of functional distinct proteins including the well-characterized antithrombin and the FGF/FGFR signal transduction system. It functions in cleaving metazoan heparan sulfate (HS) and providing carbon, nitrogen and sulfate sources for host microorganisms. It has long been used to deduce the structure of HS and heparin motifs; however, the structure of its own is unknown. Here we report the crystal structure of the HepIII from Bacteroides thetaiotaomicron at a resolution of 1.6 Å. The overall architecture of HepIII belongs to the (α/α)₅ toroid subclass with an N-terminal toroid-like domain and a C-terminal β-sandwich domain. Analysis of this high-resolution structure allows us to identify a potential HS substrate binding site in a tunnel between the two domains. A tetrasaccharide substrate bound model suggests an elimination mechanism in the HS degradation. Asn260 and His464 neutralize the carboxylic group, whereas Tyr314 serves both as a general base in C-5 proton abstraction, and a general acid in a proton donation to reconstitute the terminal hydroxyl group, respectively. The structure of HepIII and the proposed reaction model provide a molecular basis for its potential practical utilization and the mechanism of its eliminative degradation for HS polysaccarides.
Amino Acid Sequence ; Bacteroides ; enzymology ; Catalytic Domain ; Crystallography, X-Ray ; Heparitin Sulfate ; metabolism ; Kinetics ; Models, Molecular ; Molecular Sequence Data ; Polysaccharide-Lyases ; chemistry ; metabolism ; Substrate Specificity

BACKGROUND:A few of studies have showed similar efficacy and safety between domestic clopidogrel (Talcom?) and imported clopidogrel (Plavix?) in patients after percutaneous coronary intervention, but there is lack of large-scale, large sample, and prospective clinical comparative study in China.
OBJECTIVE:To compare the efficacy and safety of Talcom?and Plavix?on percutaneous coronary intervention.
METHODS:Total y 1 798 patients with Coronary atherosclerotic heart disease who received percutaneous coronary interventions were divided to two groups:Talcom?group (n=1 104) and Plavix?group (n=694). 300 mg clopidogrel was administrated oral y before percutaneous coronary intervention fol owed by 75 mg/d clopidogrel sequential y for 1 year. Al the patients were fol owed for 3-28 months to observe the incidence rate of stent thrombosis at acute, subacute, late, and very late stage, major adverse cardiac events of combination end point (including myocardial infarction, cardiac death, and stroke), and correlated adverse reactions, such as bleeding.
RESULTS AND CONCLUSION:There were no significant differences in the incidence of stent thrombosis, target vessel revascularization, cardiac death, bleeding, major bleeding and major adverse cardiac events of combination end point between Talcom?group and Plavix?group. In addition, event-free survival also showed no difference between the two groups. After treatment, white blood cellcount, erythrocyte count, hemoglobin, hematocrit, platelet count were significantly decreased in both the two groups (P<0.05). Hemoglobin level in the Talcom?group was fewer than that in the Plavix?group (P<0.05). The results suggest that effects and safety of Talcom?are similar to those of Plavix?for percutaneous coronary interventions.

Objective To investigate the methods and internal quality control ( IQC ) leucorrhea routine examinationin clinical laboratories of medical institutions in Guizhou Province.Methods In 2009, 97 clinical laboratories were randomly selected for the first investigation.At the same time, staffs in theinvestigated laboratories were educated on the importance of IQC.The second investigation of the same items was carried out in 2011 inthe same laboratories.The results of the two investigations were analyzed byChi-square test.Results 2009 and 2011 numbers of laboratories thoseonly used normal saline suspension method for leucorrhea examination were 17and 16 (χ2 =0.037, P >0.05 ) respectively, used bothnormal saline and 10%KOH suspension methodswere 16and 2(χ2 =12.003,P<0.01), used staining method were 64and 79(χ2 =5.488,P<0.05), both used suspension and staining methods were 60and 73(χ2 =4.041, P<0.05), used normal salinesuspension method combined with Wright stain and Gram staining methods were3and 28(χ2 =23.996,P<0.01) respectively.Numbers of Laboratoriespracticing IQC were 2and 88in 2009 and 2011 respectivly(χ2 =153.293,P <0.01).Conclusions Currently, the most common used method for leucorrhea routine examination is suspension.Through the investigations and education, the quality ofleucorrhea routine examination was improved in Guizhou Province.

OBJECTIVE: According to the digital image features of corneal opacity, a multi classification model of support vector machine (SVM) was established to explore the objective quantification method of corneal opacity. METHODS: The cornea digital images of dead pigs were collected, part of the color features and texture features were extracted according to the previous experience, and the SVM multi classification model was established. The test results of the model were evaluated by precision, sensitivity and RESULTS: In the classification of corneal opacity, the highest CONCLUSIONS The SVM multi classification model can classify the degree of corneal opacity.
Animals ; Corneal Opacity ; Support Vector Machine ; Swine