The T₂ structure of polycrystalline cubic human insulin.

ABSTRACT: The polymorphism of human insulin upon pH variation was characterized via X-ray powder diffraction, employing a crystallization protocol previously established for co-crystallization with phenolic derivatives. Two distinct rhombohedral (R3) polymorphs and one cubic (I2₁3) polymorph were identified with increasing pH, corresponding to the T₆, T₃R₃^f and T₂ conformations of insulin, respectively. The structure of the cubic T₂ polymorph was determined via multi-profile stereochemically restrained Rietveld refinement at 2.7 Å resolution. This constitutes the first cubic insulin structure to be determined from crystals grown in the presence of zinc ions, although no zinc binding was observed. The differences of the poly

SUBMITTER: Triandafillidis DP 

PROVIDER: S-EPMC10167666 | biostudies-literature | 2023 May

REPOSITORIES: biostudies-literature