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arXiv · 0802.1034

Physical limits on computation by assemblies of allosteric proteins

John M. Robinson
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Abstract

Assemblies of allosteric proteins, nano-scale Brownian computers, are the principle information processing devices in biology. The troponin C-troponin I (TnC-TnI) complex, the Ca$^{2+}$-sensitive regulatory switch of the heart, is a paradigm for Brownian computation. TnC and TnI specialize in sensing (reading) and reporting (writing) tasks of computation. We have examined this complex using a newly developed phenomenological model of allostery. Nearest-neighbor-limited interactions among members of the assembly place previously unrecognized constrains the topology of the system's free energy landscape and generate degenerate transition probabilities. As a result, signaling fidelity and deactivation kinetics can not be simultaneously optimized. This trade-off places an upper limit on the rate of information processing by assemblies of allosteric proteins that couple to a single ligand chemical bath.

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John M. Robinson. 2008-05-22. Physical limits on computation by assemblies of allosteric proteins. https://doi.org/10.1103/physrevlett.101.178104

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