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Coupling between Global Dynamics and Signal Transduction Pathways:
A Mechanism of Allostery for Chaperonin GroEL

Chakra Chennubhotla, Zheng Yang and Ivet Bahar

 
GroELbt

Despite significant efforts toward understanding the molecular basis of allosteric communication, the mechanisms by which local energetic and conformational changes cooperatively diffuse from ligand-binding sites to distal regions across the 3-dimensional structure of allosteric proteins remain to be established. Recent experimental and theoretical evidence supports the view that allosteric communication is facilitated by the intrinsic ability of the biomolecules to undergo collective changes in structure, triggered by ligand binding. Two groups of studies recently proved to provide insights into such intrinsic, structure-induced effects: elastic network models that permit us to visualize the cooperative changes in conformation that are most readily accessible near native state conditions, and information-theoretic approaches that elucidate the most efficient pathways of signal transmission favored by the overall architecture. Using a combination of these two approaches, we highlight, by way of application to the bacterial chaperonin complex GroEL-GroES, how the most cooperative modes of motion play a role in mediating the propagation of allosteric signals. A functional coupling between the global dynamics sampled under equilibrium conditions and the signal transduction pathways inherently favored by network topology appears to control allosteric effects.

Related publication: Chakra Chennubhotla, Zheng Yang and Ivet Bahar (2008) Coupling between Global Dynamics and Signal Transduction Pathways: A Mechanism of Allostery for Chaperonin GroEL. Mol BioSyst 4: 287-292.


 

GroEL Mode1

Inter-Ring salt Bridges

The left animation shows the first nonzero eigenmode of the GroEL-GroES complex. The slowest mode of the GroEL-GroES complex is torsional motion around the cylindrical axis of symmetry. The right animation shows the redistribution of interactions at the interface of cis and trans rings, caused by the global motion of the chaperonin GroEL-GroES. For more details see: Mol BioSyst 4: 287-292

 

Download the GroEL-GroES collective mode and the inter-ring interaction shown in PyMOL: GroEL-saltbridges.pse
( PyMOL is required to open the pse file)

 

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