Optimizing the refinement of merohedrally twinned P6₁ HIV-1 protease-inhibitor cocrystal structures.

ABSTRACT: Twinning is a crystal-growth anomaly in which protein monomers exist in different orientations but are related in a specific way, causing diffraction reflections to overlap. Twinning imposes additional symmetry on the data, often leading to the assignment of a higher symmetry space group. Specifically, in merohedral twinning, reflections from each monomer overlap and require a twin law to model unique structural data from overlapping reflections. Neglecting twinning in the crystallographic analysis of quasi-rotationally symmetric homo-oligomeric protein structures can mask the degree of structural non-identity between monomers. In particular, any deviations from perfect symmetry will be lost if higher than appropriate symmetry is applied during crystallographic analysis. Such cases warrant

SUBMITTER: Lockbaum GJ 

PROVIDER: S-EPMC7057220 | biostudies-literature | 2020 Mar

REPOSITORIES: biostudies-literature