2026-09-21T19:48:18Zhttps://gupea.ub.gu.se/server/oai/request

oai:gupea.ub.gu.se:2077/270262013-04-23T12:44:23Zcom_2077_9527com_2077_4716com_2077_10556col_2077_9528col_2077_10557

Malmerberg, Erik 2011-10-27T07:57:02Z 2011-10-27T07:57:02Z 2011-10-27 978-91-628-8371-3 http://hdl.handle.net/2077/27026 Rhodopsins are a family of light-sensitive proteins found in the cellular membranes of a wide range of living organisms. These membrane proteins share a common molecular architecture and are able to use light energy to perform a variety of different biological functions. Mapping the conformational changes required for these proteins to function is important for understanding how light energy is used for energy transduction and sensory perception in biological systems. In order to visualize these conformational changes over time, the emerging technique of time-resolved wide angle X-ray scattering (TR-WAXS) was employed. Several technical and analytical developments of this solution based method were made during the course of this work, including the development of a new data collection strategy based on a rapid readout X-ray detector. The light-driven proton pumps bacteriorhodopsin and proteorhodopsin were the first membrane proteins to be characterized using TR-WAXS. The results from these studies indicated that significant α-helical rearrangements precede the primary proton transfer event in bacteriorhodopsin. Comparison with the evolutionary related proteorhodopsin provided important insights into shared conformational dynamics between the two proton-pumps. Proteorhodopsin was further investigated by probing the conformational changes occurring within its chromophore binding pocket, where the chromophore of proteorhodopsin was substituted with a chemically modified retinal analogue. Comparison between the native and modified form of proteorhodopsin indicated significant chromophore dependant differences in their conformational kinetics. These differences provided new insights into the coupling between retinal isomerisation and protein conformational changes. The conformational dynamics within visual rhodopsin, the primary light sensor of vertebrate vision, were also investigated using TR-WAXS. By using the rapid readout X-ray detector we were able to follow the activation of this G-protein coupled receptor in real-time. Structural analysis further indicated that dramatic conformational changes are associated with the activation of this receptor. eng Paper I. Westenhoff, S., Nazarenko, E., Malmerberg, E., Davidsson, J., Katona, G. and Neutze, R. (2010) Time-resolved structural studies of protein reaction dynamics: a smorgasbord of x-ray approaches. Acta Cryst, A66, 207-219. ::doi::10.1107/S0108767309054361 Paper II. Andersson, M*., Malmerberg, E*., Westenhoff, S., Katona, G., Cammarata, M., Wohri, AB., Johansson, LC., Ewald, F., Eklund, M.., Wulff, M., Davidsson, J and Neutze, R. (2009) Structural Dynamics of Light-Driven Proton Pumps. Structure, 17, 1265-1275. ::doi::10.1016/j.str.2009.07.007 Paper III. Malmerberg, E., Omran, Z., Hub, JS., Li, X., Katona, G., Westenhoff, S., Johansson, LC., Andersson, M., Cammarata, M., Wulff, M., van der Spoel, D., Davidsson, J., Specht, A. and Neutze, R. (2011) Time- Resolved WAXS Reveals Accelerated Conformational Changes in Iodoretinal-Substituted Proteorhodopsin. Biophys J,101, 1345-1353. ::doi::10.1016/j.bpj.2011.07.050 Paper IV. Westenhoff, S*., Malmerberg, E.*, Arnlund, D., Johansson, L., Nazarenko, E., Cammarata, M., Davidsson, J., Chaptal, V., Abramson, J., Katona, G., Menzel, A. and Neutze, R. (2010) Rapid readout detector captures protein time-resolved WAXS. Nat Methods, 7, 775-776 ::doi::10.1038/nmeth1010-775c Paper V. Malmerberg, E, Katona, G., Bovee, P., Westenhoff, S., Johansson, LC., Arnlund, D., Nazarenko, E., Menzel, A., de Grip, WJ. and Neutze, R. (2011). Conformational Activation of Rhodopsin Probed by Time-resolved Wide Angle X-ray Scattering. (manuscript) Time-resolved wide Angle X-ray Scattering Retinylidene proteins Rhodopsin Bacteriorhodopsin Proteorhodopsin Conformational Dynamics of Rhodopsins Visualized by Time-resolved Wide Angle X-ray Scattering Text Doctoral thesis Doctor of Philosophy erik.malmerberg@chem.gu.se University of Gothenburg. Faculty of Science Department of Chemistry ; Institutionen för kemi Fredagen den 18:e november 2011 kl. 09.00 i KB-salen, Institutionen för kemi, Kemigården 4, Göteborg. 2011-11-18 MNF open.access