Rate promoting vibrations

The study of proton transfer in solution with coupling to a rate promoting vibration in the sense we discussed above, was pioneered by Borgis and Hanes. They used a Marcus-like model with the important addition that the tunneling matrix element between the reactant and product states is written as... 

Note the interesting temperature dependence of the rate. Since Eq. (31) implies that ao > otH, the rate equation Eq. (32) suggests that the rate promoting vibration will reduce the KIE. Hynes and eo-workers have extended their theory to the case of biased PES... 

Antoniou, D. and Schwartz, S.D. (2001) Internal enzyme motions as a source of catalytic activity rate-promoting vibrations and hydrogen tunneling, J. Chem. Phys. B 105, 5553-5558. 

Quantum theory of proton transfer 317 Rate-promoting vibrations 320... 

The structure of this review is as follows. In Section 2 we will review the concept of rate-promoting vibrations. We will first need to review briefly the theory of... 

We will now present examples of enzymatic systems where we applied the ideas and formalism of the previous section, and we were able to identify rate-promoting vibrations. 

In this section we will examine other kinds of correlated protein motions (with ps- or ns-timescales) and methods that can identify them. The rate-promoting vibrations we examined in the previous section are just one example of correlated protein motions. Because promoting vibrations involve residues in the immediate vicinity of donor and acceptor, it was relatively easy to identify them. In the more general case of extended correlated motions, it would be a challenge to identify residues that take part in them. In this section we describe two methods that have been successfully used for identifying atomic motions of interest, the TPS and the ED method. We will apply them to two enzymes we already studied in the previous section, LDH and PNP. 

The rate-promoting vibrations we examined earlier are fluctuations within a single conformation. The problem we want to address is, whether there are some conformations which favor catalysis, for example, because in them the average... 

D. Antoniou, S. D. Schwartz, Internal Enzyme Motions as a Source of Catalytic Activity Rate Promoting Vibrations and Hydrogen Tunneling, J. Phys. Chem. B, 105, 5553-5558 (2001). 

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