ABSTRACT
We constructed the CAP2NC prokaryotic expression vector of HIV-1 NL4-3 strain and obtained relatively pure CAP2NC protein by optimizing its purification conditions to explore its in vitro self-assembly conditions. Primers were designed according to the CAP2NC DNA sequence of HIV-1 NL4-3 strain. The target gene was amplified by PCR and cloned into prokaryotic expression vector pTO-T7. Then the recombinant strain was transformed into Escherichia coli BL21 (DE3). IPTG induced protein expression, then the protein was purified by hydrophobic chromatography. SDS-PAGE and Western blotting were performed to analyze the target protein, and the biological activity of the antigen was identified through ELISA. The self-assembly of CAP2NC protein was analyzed by transmission electron microscopy and gel filtration chromatography. The protein had good reaction with the specific antibodies of p24 and formed different structures in various conditions. When 10% yeast RNA was added to the protein complex, the recombinant protein only formed into a tubular structure, which was similar to the self-assembled structure of the HIV-1 virus capsid. The results showed that the HIV-1 CAP2NC protein had in vitro self-assembly activity, and the RNA affected the structure of CAP2NC protein assembly. The protein can be used as a simple and effective molecular model to study its structure, and then it can provide a reference for the study of HIV immature virus particles.
ABSTRACT
Objective To explore the abilities and personal qualities that medical undergraduates need for their future clinical work, and develop their competency model. Methods The self-made ques-tionnaire survey on medical undergraduates' competencies was conducted among the 1326 medical under-graduates in a medical university by using the cluster sampling method, and the 1099 effective question-naires were collected with effective rates of 82.88%. The exploratory factor analysis was used to analyze the internal structure of competency item and to build the competency model. The rating method was used to calculate the weight of each competency item. Results The overall Cronbach's alpha coefficient of the competency questionnaire was 0.965, and the coefficient of each dimension was above 0.832. The KMO statistic value was 0.970, and the probability associated with Bartlett test statistic was P=0.000, showing that the questionnaire has high reliability and validity. The competency model of medical undergraduates covers six aspects, namely, craftsmanship, personal qualities, professional learning, interpersonal communication, psychological adaptation and the pursuit of excellence, which contain 49 factors. The cumulative variance contribution rate was 54.729%. The weights of these six aspects in the model were 0.204 4, 0.202 1, 0.175 3, 0.158 8, 0.137 6 and 0.121 8 respectively. Conclusion The competency model of undergraduate medi-cal students has a certain scientific and practical value, which can provide new evaluation methods and ideas for medical education objectives, quality assurance, teaching evaluation, medical personnel selection and training.