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Papers by mihai pop
Advances in Computers, 2004
Protein Expression and Purification, 2006
In this report, we describe an optimized system for the eYcient overexpression, puriWcation, and ... more In this report, we describe an optimized system for the eYcient overexpression, puriWcation, and refolding of secreted bacterial proteins. Candidate secreted proteins were produced recombinantly in Escherichia coli as Tobacco Etch Virus protease-cleavable hexahistidine-cmyc eptiope fusion proteins. Without regard to their initial solubility, recombinant fusion proteins were extracted from whole cells with guanidium chloride, puriWed under denaturing conditions by immobilized metal aYnity chromatography, and refolded by rapid dilution into a solution containing only Tris buVer and sodium chloride. Following concentration on the same resin under native conditions, each protein was eluted for further puriWcation and/or characterization. Preliminary studies on a test set of 12 secreted proteins ranging in size from 13 to 130 kDa yielded between 10 and 50 mg of fusion protein per liter of induced culture at greater than 90% purity, as judged by Coomassie-stained SDS-PAGE. Of the nine proteins further puriWed, analytical gel Wltration chromatography indicated that each was a monomer in solution and circular dichroism spectroscopy revealed that each had adopted a well-deWned secondary structure. While there are many potential applications for this system, the results presented here suggest that it will be particularly useful for investigators employing structural approaches to understand protein function, as attested to by the crystal structures of three proteins puriWed using this meth
Journal of Bacteriology, 2009
Anaplasma marginale subsp. centrale is a naturally attenuated subtype that has been used as a vac... more Anaplasma marginale subsp. centrale is a naturally attenuated subtype that has been used as a vaccine for a century. We sequenced the genome of this organism and compared it to those of virulent senso stricto A. marginale strains. The comparison markedly narrows the number of outer membrane protein candidates for development of a safer inactivated vaccine and provides insight into the diversity among strains of senso lato A. marginale .
Journal of Cataract and Refractive Surgery, 2002
To study in situ the intraocular position of the Artisan iris-claw intraocular lens (IOL) (model ... more To study in situ the intraocular position of the Artisan iris-claw intraocular lens (IOL) (model 203) (Ophtec) in phakic hyperopic eyes using ultrasound biomicroscopy (UBM). Methods: Echograms of the anterior chamber were taken preoperatively and 24 to 317 days postoperatively in 4 eyes implanted with the Artisan IOL (power ϩ4.0 to ϩ6.0 diopters). The preoperative anterior chamber depth (ACD) and the postoperative distance between the IOL and the corneal endothelium (endotheliumϪoptic distance) and between the IOL and the lens were measured. The echograms were assessed for the effect of the IOL on iris tissue. Results: The preoperative ACD ranged from 3.10 to 3.56 mm and the postoperative endotheliumϪoptic distance, from 2.03 to 2.54 mm. The distance between the lens and the posterior surface of the IOL ranged from 0.35 to 0.79 mm. Several UBM echograms showed indentation of iris tissue by the IOL haptics and optic edge, although no pigmentary dispersion was noted. Conclusions: Adequate space was maintained between the Artisan hyperopic IOL and the corneal endothelium, angle, and crystalline lens. Haptic indentation of the iris, which could lead to pigment erosion, was observed. Preoperative gonioscopy and maintenance of normal intraocular pressure postoperatively suggest the indentation was secondary to inadequate lens vaulting relative to the high natural arch of the iris in hyperopic eyes. Shortening the haptics or increasing the lens vault might resolve this problem.
Advances in Computers, 2004
Protein Expression and Purification, 2006
In this report, we describe an optimized system for the eYcient overexpression, puriWcation, and ... more In this report, we describe an optimized system for the eYcient overexpression, puriWcation, and refolding of secreted bacterial proteins. Candidate secreted proteins were produced recombinantly in Escherichia coli as Tobacco Etch Virus protease-cleavable hexahistidine-cmyc eptiope fusion proteins. Without regard to their initial solubility, recombinant fusion proteins were extracted from whole cells with guanidium chloride, puriWed under denaturing conditions by immobilized metal aYnity chromatography, and refolded by rapid dilution into a solution containing only Tris buVer and sodium chloride. Following concentration on the same resin under native conditions, each protein was eluted for further puriWcation and/or characterization. Preliminary studies on a test set of 12 secreted proteins ranging in size from 13 to 130 kDa yielded between 10 and 50 mg of fusion protein per liter of induced culture at greater than 90% purity, as judged by Coomassie-stained SDS-PAGE. Of the nine proteins further puriWed, analytical gel Wltration chromatography indicated that each was a monomer in solution and circular dichroism spectroscopy revealed that each had adopted a well-deWned secondary structure. While there are many potential applications for this system, the results presented here suggest that it will be particularly useful for investigators employing structural approaches to understand protein function, as attested to by the crystal structures of three proteins puriWed using this meth
Journal of Bacteriology, 2009
Anaplasma marginale subsp. centrale is a naturally attenuated subtype that has been used as a vac... more Anaplasma marginale subsp. centrale is a naturally attenuated subtype that has been used as a vaccine for a century. We sequenced the genome of this organism and compared it to those of virulent senso stricto A. marginale strains. The comparison markedly narrows the number of outer membrane protein candidates for development of a safer inactivated vaccine and provides insight into the diversity among strains of senso lato A. marginale .
Journal of Cataract and Refractive Surgery, 2002
To study in situ the intraocular position of the Artisan iris-claw intraocular lens (IOL) (model ... more To study in situ the intraocular position of the Artisan iris-claw intraocular lens (IOL) (model 203) (Ophtec) in phakic hyperopic eyes using ultrasound biomicroscopy (UBM). Methods: Echograms of the anterior chamber were taken preoperatively and 24 to 317 days postoperatively in 4 eyes implanted with the Artisan IOL (power ϩ4.0 to ϩ6.0 diopters). The preoperative anterior chamber depth (ACD) and the postoperative distance between the IOL and the corneal endothelium (endotheliumϪoptic distance) and between the IOL and the lens were measured. The echograms were assessed for the effect of the IOL on iris tissue. Results: The preoperative ACD ranged from 3.10 to 3.56 mm and the postoperative endotheliumϪoptic distance, from 2.03 to 2.54 mm. The distance between the lens and the posterior surface of the IOL ranged from 0.35 to 0.79 mm. Several UBM echograms showed indentation of iris tissue by the IOL haptics and optic edge, although no pigmentary dispersion was noted. Conclusions: Adequate space was maintained between the Artisan hyperopic IOL and the corneal endothelium, angle, and crystalline lens. Haptic indentation of the iris, which could lead to pigment erosion, was observed. Preoperative gonioscopy and maintenance of normal intraocular pressure postoperatively suggest the indentation was secondary to inadequate lens vaulting relative to the high natural arch of the iris in hyperopic eyes. Shortening the haptics or increasing the lens vault might resolve this problem.