title: Physical limits on computation by assemblies of allosteric proteins.
abstract: Assemblies of allosteric proteins are the principle information processing devices in biology. Using the Ca2+-sensitive cardiac regulatory assembly as a paradigm for Brownian computation, I examine how system complexity and system resetting impose physical limits on computation. Nearest-neighbor-limited interactions among assembly components constrain the topology of the system's macrostate free energy landscape and produce degenerate transition probabilities. As a result, signaling fidelity and deactivation kinetics cannot be simultaneously optimized. This imposes an upper limit on the rate of information processing by assemblies of allosteric proteins that couple to a single ligand type.
authors.affiliation: Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA. jmr@uab.edu
authors.forename: John M
authors.initials: JM
authors.lastname: Robinson
mesh_terms: D008024:Ligands; D008954:Models, Biological; D044169:Receptors, Calcium-Sensing / Q000737:chemistry / Q000378:metabolism; D013816:Thermodynamics; D019209:Troponin C / Q000737:chemistry / Q000378:metabolism*; D019210:Troponin I / Q000737:chemistry / Q000378:metabolism*
chemical_list: D008024:Ligands; D044169:Receptors, Calcium-Sensing; D019209:Troponin C; D019210:Troponin I