The work of and Dr. Tsvi Tlusty and research student Yonatan Savir of the Weizmann Institute’s Physics of Complex Systems Department suggests a possible answer. A simple biophysical model they developed indicates that in picking out the target molecule from a crowd of look-alikes, the recognizer has an advantage if it’s slightly off-target. This may appear to be counterintuitive: Why search for a key that does not match its lock exactly, and then require that the imperfect key warp its shape to fit the lock"
The researchers’ model shows that the key’s deformation actually helps in discerning the right target. Although the energy required to deform the molecular key slightly lowers the probability of its binding to the right target, it also reduces the probability that it will bind to a wrong one by quite a bit. Thus, the quality of recognition – i.e. the ratio of the right to wrong binding probabilities – increases.
This simple mechanism is coined 'conformational proofreading' and may explain the observed deformations in many biological recognition systems. Furthermore, conformational proofreading may turn out be a crucial factor affecting the evolution of bio-logical systems, and it may also be useful in the design of artificial molecular recognition systems.
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Dr. Tsvi Tlusty’s research is supported by the Clore Center for Biological Physics; the Asher and Jeannette Alhadeff Research Award; and the Philip M. Klutznick Fund for Research. |
