Condensed Matter Physics Seminar
Thursday, September 28, 2000, 2 p.m.
Plant Sciences Building, Room 1130
Engineering Aspects of Enzymatic Signal Transduction: Photo-receptors
(Bell Laboratories, NJ)
Abstract: The basic module of enzymatic amplification is an irreversible
cycle of messenger activation/deactivation by a pair of ``push-pull" enzymes.
We analyze this module in terms of gain, bandwidth, noise and power consumption.
The enzymatic signal transduction cascade is viewed as as information channel,
the design of which is governed by the statistical properties of the input
and the noise and dynamic range constraint of the output. On the
example of vertebrate photo-transduction cascade, we demonstrate that of
the relevant engineering parameters are controlled by enzyme concentrations.
From functional constraints, we could derive bounds on the protein numbers
and compare with observed values. We also study a possible mechanism
underlying the low variability of single photon response despite stochastic
fluctuations in the life span of an activated Rhodopsin molecule.
Host: Amitava Chattopadhyay
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