Xi Zhao obtained his PhD in 2007 from Jilin University and was a visiting scholar from University of California Irvine, department of Chemistry. Now he is a associate professorof Institute of Theoretical Chemistry, Jilin University. His researches focus on biomolecular simulation. He has published more than 25 papers in reputed journals.
The nucleobase/cation symporter 2 (NCS2) family proteins affect several crucial processes such as the uptake of nucleobases and transport of vitamin C for most living organisms on Earth. Uracil Transporter(UraA)from the Escherichia coli , known as the representative NCS2 protein, catalyzes symport of a uracil and an H+ via an alternating access mechanism. The experimental results shows that protonation state changes of some key amino acid residues can regulate conformational changes of UraA, but the details and process of conformational transitions are unknown during transporting uracil. We study that the different protonation states of Glu241, Glu290 and His 245 effect on UraA conformational transitions using molecular simulations. We observed that inward-open conformation reverts to the outward-open conformation of UraA in DDP+L (Glu241 and Glu290 deprotonation, His 245 protonation, substrate exits) and DDP-L (Glu241 and Glu290 deprotonation, His 245 protonation, no substrate exits). The results show that the presence of proton in the His245 directly restricts the motions of gate domain and further changes motion modes between core domain and gate domain. Therefore, we propose a new transport model for UraA.
Abi Santhosh Aprem has completed his PhD at the age of 29 years from Mahatma Gandhi University, Kottayam, Kerala, India. He is currently the Deputy Vice President of Corporate R&D Centre of HLL Lifecare Ltd. He has published more than 26 papers in peer reviewed journals.
Copper Intra uterine devices represent an important contraceptive option for nearly 160 million women worldwide . The main attraction of copper IUD is that it is comparatively less expensive and highly effective (99%) over other long term methods of contraception . Major side effect related to a copper bearing IUD is increased menstrual bleeding, cramping and abdominal pain. Research results showed that this is due to the high corrosive rate during the first few months of insertion [3, 4]. In the present study PLGA films having proper degradation period were prepared by extrusion method which could prevent initial bulk release of copper ions from a copper intrauterine device, leading to increased efficacy and acceptability. Based on our experiments, we proved that PLGA film with thickness 0.1±0.02 mm coated over the copper Intra uterine device is safe and effective in controlling copper ion release in the required level of contraception. The Biodegradable polymer coated copper T (Coated CuT) has been characterized and Intracutaneous irritation studies showed that Coated CuT is a non irritant and non sensitizer. The results of acute systemic toxicity study suggested that Coated CuT did not induce any toxic symptoms till the end of the experimental period and there was neither development of gross abnormalities nor pathological lesions observed in any of the tissues during the histopathological evaluation. Hence the novel device meets the requirements of the standard practices recommended for evaluating the biological activity for implantable devices. A randomized multicenter clinical evaluation of the device is in progress on 100 subjects in India.