Đang chuẩn bị nút TẢI XUỐNG, xin hãy chờ
Tải xuống
Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Engineering of the E. coli Outer Membrane Protein FhuA to overcome the Hydrophobic Mismatch in Thick Polymeric Membranes | Muhammad et al. Journal of Nanobiotechnology 2011 9 8 http www.jnanobiotechnology.eom content 9 1 8 JOURNAL OF NANOBIOTECHNOLOGY RESEARCH Open Access Engineering of the E. coli Outer Membrane Protein FhuA to overcome the Hydrophobic Mismatch in Thick Polymeric Membranes Noor Muhammad Tamara Dworeck Marco Fioroni Ulrich Schwaneberg Abstract Background Channel proteins like the engineered FhuA A1-159 often cannot insert into thick polymeric membranes due to a mismatch between the hydrophobic surface of the protein and the hydrophobic surface of the polymer membrane. To address this problem usually specific block copolymers are synthesized to facilitate protein insertion. Within this study in a reverse approach we match the protein to the polymer instead of matching the polymer to the protein. Results To increase the FhuA A1-159 hydrophobic surface by 1 nm the last 5 amino acids of each of the 22 p-sheets prior to the more regular periplasmatic p-turns were doubled leading to an extended FhuA A1-159 FhuA A1-159 Ext . The secondary structure prediction and CD spectroscopy indicate the p-barrel folding of FhuA A1-159 Ext. The FhuA A1-159 Ext insertion and functionality within a nanocontainer polymeric membrane based on the triblock copolymer PIB1000-PEG6000-PIB1000 PIB polyisobutylene PEG polyethyleneglycol has been proven by kinetic analysis using the HRP-TMB assay HRP Horse Radish Peroxidase TMB 3 3 5 5 -tetramethylbenzidine . Identical experiments with the unmodified FhuA A1-159 report no kinetics and presumably no insertion into the PIB1000-PEG6000-PIB1000 membrane. Furthermore labeling of the Lys-NH2 groups present in the FhuA A1-159 Ext channel leads to controllability of in out flux of substrates and products from the nanocontainer. Conclusion Using a simple semi rational approach the protein s hydrophobic transmembrane region was increased by 1 nm leading to a predicted lower hydrophobic mismatch between the protein and polymer membrane minimizing the insertion