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Noam Agmon: "Proton Mobility in Water and Proteins"

Wann 10.05.2012
von 13:15 bis 14:00
Wo FRIAS Seminar Room, Albertstr. 19, 79104 Freiburg
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Noam Agmon
Department of Physical Chemistry, Hebrew University, Jerusalem, Israel

 

Proton Mobility in Water and Proteins

Proton mobility is important for reactions in solution and biological systems. Recent studies reveal a range of mechanisms, more stochastic in bulk liquid water, concerted multi-proton hopping along short water-wires connecting acid and base in solution, and a "proton collecting antenna" in the green fluorescent protein (GFP).

In room temperature bulk water, MS-EVB simulations revealed a dynamically distorted hydronium (H3O+) undergoing the "special pair dance". Eventually a protonated dimer (H5O2+ cation) is formed, allowing proton hopping between these two water molecules. The IR band of this "proton-transfer mode" has been identified using a "clusters-in-liquid" approach.

A high resolution X-ray structure of GFP revealed an internal wire connecting its chromophore to a putative "proton collecting antenna" on a negative surface patch. It could possibly be recruiting a proton from solution to replenish that which escaped following photo-excitation.