Before revision: We study physical limits of chemical sensing by a single chemotactic cell with cooperative chemoreceptors on the cell surface . We derive general formula for the gradient sensing limit from the uncertainty in instantaneous receptor activity configurations and find that cooperativity by non-adaptive receptors could significantly lower the sensing limit at the biochemically-relevant regime of balanced free energy difference between active and inactive receptor states . Cooperativity by adaptive receptors are beneficial to gradient sensing under a broad range of background concentrations.
After revision: We study physical limits of chemical sensing by a single chemotactic cell with cooperative chemoreceptors on the cell surface and derive general formula for the gradient sensing limit from the uncertainty in instantaneous receptor activity configurations and find that cooperativity by non-adaptive receptors could significantly lower the sensing limit at the biochemically-relevant regime of balanced free energy difference between active and inactive receptor states . Cooperativity by adaptive receptors are beneficial to gradient sensing under a broad range of background concentrations.