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Quadratic Programming Approach to Fit Protein Complexes into Electron Density Maps

Roman Pogodin 1, 2 Alexander Katrutsa 3, 1, 2 Sergei Grudinin 3
3 NANO-D - Algorithms for Modeling and Simulation of Nanosystems
Inria Grenoble - Rhône-Alpes, Grenoble INP - Institut polytechnique de Grenoble - Grenoble Institute of Technology, LJK - Laboratoire Jean Kuntzmann
Abstract : The paper investigates the problem of fitting protein complexes into electron density maps. They are represented by high-resolution cryoEM density maps converted into overlapping matrices and partly show a structure of a complex. The general purpose is to define positions of all proteins inside it. This problem is known to be NP-hard, since it lays in the field of combinatorial optimization over a set of discrete states of the complex. We introduce quadratic programming approaches to the problem. To find an approximate solution, we convert a density map into an overlapping matrix, which is generally indefinite. Since the matrix is indefinite, the optimization problem for the corresponding quadratic form is non-convex. To treat non-convexity of the optimization problem, we use different convex relaxations to find which set of proteins minimizes the quadratic form best.
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Submitted on : Monday, December 19, 2016 - 12:46:00 PM
Last modification on : Wednesday, December 1, 2021 - 2:36:21 PM
Long-term archiving on: : Tuesday, March 21, 2017 - 8:35:22 AM


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  • HAL Id : hal-01419380, version 1


Roman Pogodin, Alexander Katrutsa, Sergei Grudinin. Quadratic Programming Approach to Fit Protein Complexes into Electron Density Maps. Information Technology and Systems 2016, Sep 2016, Repino, St. Petersburg, Russia. ⟨hal-01419380v1⟩



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