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Free keywords:
Bacterial outer-membrane; Rhodobacter-capsulatus; Channel; Delafieldii; Resolution; Protein.; Chemistry & analysis.
Abstract:
Omp32, the strongly anion-selective porin from Comamonas acidovorans, has been crystallized. Two crystal forms were observed, both of which belong to space group R3, but exhibit different cell dimensions a = b = 106.7, c = 140.6 Angstrom (crystal form I) and a = b = 87.1, c = 135.3 Angstrom (crystal form II) with one trimer per asymmetric unit. The crystals diffract to 2.2 and 2.3 Angstrom resolution, respectively. Omp32 was chemically modified by introducing negative charges through succinylation. The number and positions of the individual modifications were determined using mass spectrometry and X-ray crystallography. Chemically modified porins yielded crystals of a third form, also of space group R3 but with cell constants of a = b = 109.3 and c = 263.2 Angstrom (crystal form III), showing a virtually doubled c axis. Crystals of form III diffract to 3.5 Angstrom resolution. [References: 21]
