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Electrostatic properties of the anion selective porin Omp32 from Delftia acidovorans and of the arginine cluster of bacterial porins.

ABSTRACT: The functional properties of the anion-selective porin Omp32 from the bacterium Delftia acidovorans, formerly Comamonas acidovorans, are determined by the particularly narrow channel constriction and the electrostatic field inside and outside the pore. A cluster of arginines (Arg 38, Arg 75, and Arg 133) determines the electrostatic field close to the constriction zone. Stacked amino acids carrying charges are prone to drastic pK(a) shifts. However, optimized calculations of the titration behavior of charged groups, based on the finite-difference Poisson-Boltzmann technique, suggest that all the arginines are charged at physiological pH. Protonation of the clustered arginines is stabilized by one buried glutamate residue (Glu 58), which is strongly interacting with Arg 75 and Arg 38. This functional arrangement of three charged amino acid residues is of general significance because it is found in the constriction zones of all known 16-stranded porins from the alpha-, beta-, and gamma-proteobacteria.

SUBMITTER: Zachariae U

PROVIDER: S-EPMC2373638 | biostudies-literature | 2002 Jun

REPOSITORIES: biostudies-literature

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Electrostatic properties of the anion selective porin Omp32 from Delftia acidovorans and of the arginine cluster of bacterial porins.

Zachariae Ulrich U Koumanov Assen A Engelhardt Harald H Karshikoff Andrey A

Protein science : a publication of the Protein Society 20020601 6

The functional properties of the anion-selective porin Omp32 from the bacterium Delftia acidovorans, formerly Comamonas acidovorans, are determined by the particularly narrow channel constriction and the electrostatic field inside and outside the pore. A cluster of arginines (Arg 38, Arg 75, and Arg 133) determines the electrostatic field close to the constriction zone. Stacked amino acids carrying charges are prone to drastic pK(a) shifts. However, optimized calculations of the titration behavi ...[more]

PMID: 12021430

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Dataset Information

Electrostatic properties of the anion selective porin Omp32 from Delftia acidovorans and of the arginine cluster of bacterial porins.

Publications

Electrostatic properties of the anion selective porin Omp32 from Delftia acidovorans and of the arginine cluster of bacterial porins.

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