The native serine protease proteinase K binds two calcium cations. It has been reported that Ca(2+) removal decreased the enzyme's thermal stability and to some extent the substrate affinity, but has discrepant effects on catalytic activity of the enzyme. Molecular dynamics simulations were performed on the Ca(2+)-bound and Ca(2+)-free proteases to investigate the mechanism by which the calciums affect the structural stability, molecular motions, and catalytic activity of proteinase K. Very similar structural properties were observed between these two forms of proteinase K during simulations; and several long-lived hydrogen bonds and salt bridges common to both forms of proteinase K were found to be crucial in maintaining the local conformations around these two Ca(2+) sites. Although Ca(2+) removal enhanced the overall flexibility of proteinase K, the flexibility in a limited number of segments surrounding the substrate-binding pockets decreased. The largest differences in the equilibrium structures of the two simulations indicate that, upon the removal of Ca(2+), the large concerted motion originating from the Ca1 site can transmit to the substrate-binding regions but not to the catalytic triad residues. In conjunction with the large overlap of the essential subspaces between the two simulations, these results not only provide insight into the dynamics of the underlying molecular mechanism responsible for the unchanged enzymatic activity as well as the decreased thermal stability and substrate affinity of proteinase K upon Ca(2+) removal, but also complement the experimentally determined structural and biochemical data.
Liver international : official journal of the International Association for the Study of the Liver,2016年37(1):19-31 ISSN：1478-3223
[Pan, Qiuwei] Department of Gastroenterology and Hepatology, Erasmus MC-University Medical Center Rotterdam, Rotterdam, the Netherlands. email@example.com;[Wang, Wenshi; Peppelenbosch, Maikel P; de Man, Robert A; Hakim, Mohamad S] Department of Gastroenterology and Hepatology, Erasmus MC-University Medical Center Rotterdam, Rotterdam, the Netherlands;[Geng, Jiawei] Department of Infectious Diseases, The First People's Hospital of Yunnan Province, Kunming, China;[Bramer, Wichor M] Medical Library, Erasmus MC-University Medical Center Rotterdam, Rotterdam, the Netherlands;[Huang, Fen] Medical Faculty, Kunming University of Science and Technology, Kunming, China
[Pan, Qiuwei] Department of Gastroenterology and Hepatology, Erasmus MC-University Medical Center Rotterdam, Rotterdam, the Netherlands. q.
global burden;hepatitis E;outbreaks
Hepatitis E virus (HEV) is responsible for repeated water-borne outbreaks since the past century, representing an emerging issue in public health. However, the global burden of HEV outbreak has not been comprehensively described. We performed a systematic review of confirmed HEV outbreaks based on published literatures. HEV outbreaks have mainly been reported from Asian and African countries, and only a few from European and American countries. India represents a country with the highest number of reported HEV outbreaks. HEV genotypes 1 and 2 were responsible for most of the large outbreaks in developing countries. During the outbreaks in developing countries, a significantly higher case fatality rate was observed in pregnant women. In fact, outbreaks have occurred both in open and closed populations. The control measures mainly depend upon improvement of sanitation and hygiene. This study highlights that HEV outbreak is not new, yet it is a continuous global health problem.
Journal of the College of Physicians and Surgeons--Pakistan : JCPSP,2017年27(7):404-408 ISSN：1022-386X
[Haiyun, Luo; Xia, Li; Qun, Xuan; Ying, Guo; Jianyu, Yang] School of Basic Medical Sciences, Kunming Medical University, Kunming, Yunnan, China;[Jianping, Xie] Library, Yunnan Minzu University, Kunming, Yunnan, China;[Jianyun, Yu] Quality Monitoring and Assessment Center, Kunming Medical University, Kunming, Yunnan, China
[Xuan, Q] Kunming Med Univ, Sch Basic Med Sci, Kunming, Yunnan, Peoples R China.
Pharmacology;Mind maps;Multi-modal final examination
Objective: To determine whether students using mind maps would improve their performance in a final examination at the end of lecture-based pharmacology course. Study Design: A quasi-experimental study. Place and Duration of Study: Kunming Medical University, from September 2014 to January 2015. Methodology: One hundred and twenty-two (122) third year undergraduate medical students, starting a 48-hour lecture-based pharmacology course, volunteered to use mind maps as one of their study strategies (intervention group), while the remaining 100 students in the class continued to use their usual study strategies (control group) over the duration of the course. The performance of both groups in the final course examination was compared. Students in the intervention group also completed a questionnaire on the usefulness of mind maps during the course and in preparation for the final examination. Results: The students' performance of intervention group was superior to performance of the control group in all parts of a multi-modal final examination. For the multiple choice questions and comprehensive scores, average marks of 45.97 +/- 7.22 and 68.07 +/- 12.77, respectively were acquired by the control group, and 51.77 +/- 4.95 (p < 0.01) and 80.05 +/- 7.54 (p < 0.01), respectively by the intervention group. The median IQR scores for "filling in the blanks" questions, short answers questions and case analyses, were 6.00 (6.00), 8.00 (3.50), 8.75 (5.88), respectively for the control group, and were all significantly higher at 8.00 (4.00) (p = 0.024), 10.00 (2.00) (p < 0.001), and 11.00 (3.25) (p = 0.002), respectively for the intervention group. Questionnaire responses showed that 95.45% thought that mind maps helped them to prepare more efficiently for the final exam; 90.91% believed that mind maps helped them to better understand all of pharmacology. Ninety-one percent also thought that mind maps would help them to better understand other disciplines, and 86.36% students would like the lecturers to utilize mind mapping as an alternative to conventional teaching formats, such as the use of Power Point. Conclusion: The addition of mind maps to students' study of pharmacology at Kunming Medical University improved their performance in all aspects of a multi-modal final examination.
Brassica juncea thermosensitive male sterility Proteomics
The present study was conducted to study fertility conversion related proteins in Brassicajuncea and to reveal the molecular mechanism of temperature sensitive male sterility.Weused IEF/ SDS-PAGE and PDQuest analysis software technology to study the proteins atthe three nuclear flower bud stage in temperature sensitive genic male sterile line (TGMS)K121S under infertile and fertile temperatures.