1. Thermodynamic and kinetic stability of zwitterionic histidine: Effects of gas phase hydration.
- Author
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Lee, Sung-Sik, Kim, Ju-Young, Han, Yuna, Shim, Hyun-Jin, and Lee, Sungyul
- Subjects
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THERMODYNAMICS , *ANALYTICAL mechanics , *CHEMICAL stability , *ZWITTERIONS , *HISTIDINE , *GAS phase reactions , *HYDRATION - Abstract
We present calculations for histidine–(H 2 O) n ( n = 0–6) to examine the effects of micro-hydrating water molecules on the relative stability of the zwitterionic vs. canonical forms of histidine. We calculate the structures and Gibbs free energies of the conformers at wB97XD/6-311++G(d,p) level of theory. We find that six water molecules are required to produce the thermodynamically stable histidine zwitterion. By calculating the barriers of canonical ↔ zwitterionic transformation, we predict that both the most stable canonical and zwitterionic forms of histidine–(H 2 O) 6 may be observed in low temperature gas phase environment. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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