The relationship between bulk water and protein dynamical transitions

PHYS 686

Teresa Head-Gordon, TLHead-Gordon@lbl.gov1, Margaret E Johnson, mej47@berkeley.edu1, Cecile Malardier-Jugroot, CMalardier-Jugroot@lbl.gov1, Ard A. Louis, ard.louis@physics.ox.ac.uk2, and Rajesh K. Murarka, rkm25@cornell.edu3. (1) Department of Bioengineering, University of California, Berkeley, Berkeley, CA 94720, (2) Rudolf Peierls Centre for Theoretical Physics, Oxford University, 1 Keble Road, Oxford, OX1 3NP, United Kingdom, (3) Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853
The dynamical transition in bulk water is based on the observation that extrapolated relaxation timescales appear to diverge at a temperature of ~228K. This dynamical transition in the bulk supercooled state has been postulated to drive a corresponding dynamical transition for proteins, for the reason that the restoration of anharmonic protein motions appear above a critical temperature, and more controversially a critical hydration level, which activates motions of surface hydration water. We explore this connection with a combination of theoretical coarse-grained models of bulk water to characterize the molecular features of dynamical anomalies, quasi-elastic neutron scattering experiments that probe hydration dynamics of water confined in a concentrated solution of hydrophobic peptides in water over a temperature range of 248K to 288K, and molecular dynamics simulations of collective dynamics in these aqueous solutions.
 

Hydration: From Clusters to Aqueous Solution
8:20 AM-12:00 PM, Thursday, August 23, 2007 BCEC -- 159, Oral

Division of Physical Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007