Hydrated proteins are known to undergo a dynamical transition at around 200K. Several mechanisms have been proposed but the underlying mechanism, physical origin and relationship to water remain controversial. We studied protein dynamics inside high-pressure cryocooled protein crystals and observed a protein dynamical transition as low as 110K [1]. This unexpected protein dynamical transition precisely correlated with the cryogenic phase transition of water from high-density amorphous to low-density amorphous state [2]. The results provide new insights into the underlying mechanism of protein dynamical transition and its relationship with the unusual physical properties of supercooled water. References1. Chae Un Kim , Mark W. Tate and Sol M. Gruner (2011), Protein dynamical transition at 110 K, PNAS  108, 20897-20901.2. Chae Un Kim , Buz Barstow, Mark W. Tate and Sol M. Gruner (2009), Evidence for liquid water during the high-density to low-density amorphous ice transition, PNAS  106, 4596-4600.

Phase behavior of water and protein dynamics at cryogenic temperatures

244th National Meeting (2012)

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