Protein Preparation, Crystallization and Preliminary X-ray Crystallographic Analysis of Smu_195c From Caries Pathogen Streptococcus mutans / 生物化学与生物物理进展

Smu_195c is a protein with 86 amino acids in Streptococcus mutans, a primary pathogen for human dental caries. The specific function of Smu_195c is still unknown and there are no conserved domains in it. In order to find out its function, the gene encodes Smu_195c was cloned and expressed in E. coli as N-terminally 6*His tagged recombinant protein. Two crystal forms were obtained by the hanging drop method. Form Ⅰ belongs to space group P6122 or P6522 with the unit cell parameters a = b = 62.93 (A), c= 90.63 (A), γ=120° and form Ⅱ belongs to the space group P41212 or P43212 with the unit cell parameters a =b=57.97 (A), c = 103.51 (A).Crystals from the protein with His-tag belong to form Ⅰ, however, crystals from the protein without His-tag belong to both.

Preparation, Crystallization and Preliminary X-ray Crystallographic Analysis of Smu.776 From Caries Pathogen Streptococcus mutans / 生物化学与生物物理进展

The gene smu. 776 encodes a possible S-adenosylmethionine-dependent methyltransferase of 385 residues in Streptococcus mutans, a primary pathogen for human dental caries. The DNA fragment of smu.776 was cloned into pET28a and expressed in good amount from the E. coli strain BL21 (DE3). Smu.776 protein was purified to homogeneity in a two-step procedure ofNi2+ chelating and size exclusion chromatography. Crystals were obtained by hanging-drop vapor diffusion method and diffracted to 2.0 (A) resolution.The crystal belongs to orthorhombic space group C2 with cell dimension of a=168.47 (A), b= 50.66 (A), c=53.96 (A), β=104.22°. The asymmetric unit is expected to contain one molecule with solvent content of 51.3%.

Expression,Purification,Crystallization and Preliminary X-ray Studies of a Deoxycytidylate Deaminase From Streptococcus mutans / 生物化学与生物物理进展

Deoxycytidylate (dCMP) deaminase is an enzyme belonged to dCMP cyt deam family. The dCMP deaminase from Streptococcus mutans UA159 was cloned and expressed in E. coli, and purified to homogeneity. The FPLC size exclusion chromatography analysis reveals that the S. mutans dCMP deaminase forms hexamer in solution. The protein was crystallized using hanging drop vapour-diffusion method and diffracted to a resolution of 3.1 ?. The diffraction data were collected at BSRF beamline 3W1A. The crystals belong to P213 space group, with unit cell parameters a = b = c = 113.2 ?, ? = ? = ? = 90?. Assuming there are two subunits per asymmetric unit, the Matthews coefficient is 3.6 ?3?Da-1. This is the first crystallization report of the wild-type deoxycytidylate deaminase.

Expression, Purification, Crystallization and Preliminary X-ray Studies of a Deoxycytidylate Deaminase From Streptococcus mutans / 生物化学与生物物理进展

Deoxycytidylate (dCMP) deaminase is an enzyme belonged to dCMP cyt deam family. The dCMP deaminase from Streptococcus mutans UA159 was cloned and expressed in E. coli, and purified to homogeneity. The FPLC size exclusion chromatography analysis reveals that the S. mutans dCMP deaminase forms hexamer in solution. The protein was crystallized using hanging drop vapour-diffusion method and diffracted to a resolution of 3.1 (A). The diffraction data were collected at BSRF beamline3W1A. The crystals belong to P213 space group, with unit cell parameters a = b = c = 113.2(A), α =β = γ = 90°. Assuming there are two subunits per asymmetric unit, the Matthews coefficient is 3.6 (A)3 ·Da-1. This is the first crystallization report of the wild-type deoxycytidylate deaminase.

Protein Preparation, Crystallization and Preliminary X-ray Crystallographic Analysis of Smu.260 From Streptococcus mutans--a Cariogenic Dental Pathogen / 生物化学与生物物理进展

Smu. 260 encodes a putative protein of 200 residues in Streptococcus mutans, a primary pathogen for human dental caries. Smu. 260 was cloned into expression vector pET28a and expressed in good amount trom the E. coli strain BL21 (DE3). Smu.260 protein was purified to homogeneity in a two-step procedure of Ni2+ chelating and size exclusion chromatography. The purified protein exists in two forms, a dimer form about 46 ku with yellow color and a tetramer form without apparent color. Crystals were obtained from the dimer protein by hanging-drop vapor-diffusion method. The crystals diffracted to about 2.3 A resolution and belong to orthorhombic space group P212121 with cell dimensions of a = 89.88A, b = 90.91 A, c = 105.17 A. The asymmetric unit is expected to contain two dimers with solvent content of 53%.

Clinical study of severe complications during hysteroscopic surgeries / 中华妇产科杂志

Objective To investigate the clinical characteristics, treatment and prevention methods of severe complications during hysteroscopic procedures Methods From January 1995 to January 2001, seventeen cases with uterine perforation, heavy bleeding and fluid overload respectively were encountered during hysteroscopic procedures This analysis focuses on their diagnosis and clinical management as well as prevention methods Results Three cases with uterine perforation and seven with uncomplete perforation followed transcerivcal resection of myoma (TCRM), transcerivcal resection of adhension, transcerivcal resection of septum and transcerivcal removal of foreign body respectively, which were diagnosied by both B ultrasonography and laparoscopy and treated laparoscopically Four cases with heavey bleeding were encountered during TCRM Foley catheter was inserted into uterine cavity to stop the bleeding successfully Three cases with fluid overload were cured by diuretic agent and saline infusion There were no serious consequence happened Conclusions It is a potential high risk factor of resulting in complications that performing complicated procedures inside uterine cavity during hysteroscopic operations Pre treatment with gonadotropin releasing a and guiding with B ultrasound/ laparoscopy as well as controlling irrigation pessure are necessary for proventing above complications