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Histidine in continuum electrostatics protonation state calculations.

ABSTRACT: A modification to the standard continuum electrostatics approach to calculate protein pK(a)s, which allows for the decoupling of histidine tautomers within a two-state model, is presented. Histidine with four intrinsically coupled protonation states cannot be easily incorporated into a two-state formalism, because the interaction between the two protonatable sites of the imidazole ring is not purely electrostatic. The presented treatment, based on a single approximation of the interrelation between histidine's charge states, allows for a natural separation of the two protonatable sites associated with the imidazole ring as well as the inclusion of all protonation states within the calculation.

SUBMITTER: Couch V

PROVIDER: S-EPMC4229071 | biostudies-literature | 2011 Dec

REPOSITORIES: biostudies-literature

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Histidine in continuum electrostatics protonation state calculations.

Couch Vernon V Stuchebrukhov Alexei A

Proteins 20110830 12

A modification to the standard continuum electrostatics approach to calculate protein pK(a)s, which allows for the decoupling of histidine tautomers within a two-state model, is presented. Histidine with four intrinsically coupled protonation states cannot be easily incorporated into a two-state formalism, because the interaction between the two protonatable sites of the imidazole ring is not purely electrostatic. The presented treatment, based on a single approximation of the interrelation betw ...[more]

PMID: 22072521

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