A Brownian Dynamics computational study of the interaction of spinach plastocyanin with turnip cytochrome f: the importance of plastocyanin conformational changes.
Brownian Dynamics (BD) computer simulations were used to study electrostatic interactions between turnip cytochrome f (cyt f) and spinach plastocyanin (PC). Three different spinach PC structures were studied: The X-ray crystal structure of Xue and coworkers [(1998) Protein Sci 7:2099-2105] and the NMR structure of Musiani et al. [(2005) J Biol Chem 280:18833-18841] and Ubbink and co-workers [(1998) Structure 6:323-335]. Significant differences exist in the backbone conformation between the PC taken from Ubbink and coworkers and the other two PC structures particularly the regions surrounding G10, E59-E60, and D51. Complexes formed in BD simulations using the PC of Ubbink and colleagues had a smaller Cu-Fe distance than the other two. These results suggest that different PC conformations may exist in solution with different capabilities of forming electron-transfer-active docks. All three types of complexes show electrostatic contacts between D42, E43, and D44 on PC and K187 on cyt f as well as between E59 on PC and K58 on cyt f. However, the PC of Ubbink and coworkers reveals additional contacts between D51 and cyt f as a result of the difference in backbone configuration. A second minor complex component was observed for the PC of Ubbink and co-workers and Xue and co-workers which had contacts between K187 on cyt f and E59 and E60 on PC rather than between K187 on cyt f and D42-D44 on PC as observed for the major components. This second type of complex may represent an earlier complex which rearranges to form a final complex capable of electron transfer.
Gross
Elizabeth L
EL
Department of Biochemistry, The Ohio State University, 484 W. 12th. Ave, Columbus, OH 43235, USA. swenson.1@osu.edu
D029741:Brassica rapa / Q000378:metabolism; D003198:Computer Simulation; D045348:Cytochromes f / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D008968:Molecular Conformation; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism*; D010970:Plastocyanin / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D018724:Spinacia oleracea / Q000378:metabolism
D010940:Plant Proteins; D010970:Plastocyanin; D045348:Cytochromes f