| Regional Biophysics Meeting 2005, March 16-20, Zreče, Slovenia | [ComputModel] |
In our previous study [1] we described the method for the direct 3D computer simulation of photosynthetic electron transport processes. This method was used to build a direct 3D model of ferredoxin-dependent cyclic electron transport around pigment-protein complex photosystem 1. In this paper we further develop the direct 3D model of electron transport and apply it to study both linear and cyclic electron transport in chloroplasts. The model represents two areas of thylakoid membrane, granal area and stromal area, so the model has lateral heterogeneity. Different types of complexes are located in different areas. Photosystem 1 is mostly found in stromal area and Photosystem 2 in granal area, cytochrome complex is distributed uniformly throughout the membrane. We simulate each protein-pigment complex and mobile electron carrier as object on 3-dimensional scene, described by a set of other parameters, representing movement and interaction with other objects. Movement of the mobile carriers is simulated using Brownian dynamics approach. We take into account collisions with complexes and other mobile carriers. Interaction between complexes and mobile carriers is simulated in two steps. First, docking of the mobile carrier to the specific docking site of complex is considered. We describe docking by two parameters – effective interaction radius and the probability of docking, when mobile carrier is closer to complex, than interaction radius. The electron transfer from docked carrier to complex and electron transfer inside complex is simulated using kinetic reaction equations. Simulation results indicate that spatial organization of the thylakoid membrane plays important role in electron transfer process. The study was supported by Russian Foundation for Basic Research, projects 03-04-49048 and 04-07-90278. 1. Kovalenko, I.B., et al., Cyclic electron transport around photosystem 1: an experimental and theoretical study. Biophysics, 2003. 48(4): p. 614-623.
Email: ustinin@mail.ru
Address: Russian Federation, Moscow 119992, GSP-2 Leninskiye Gory,, Moscow State University, Biological Faculty, Chair of Biophysics, , , , , ,