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Updated: Apr 15, 2026

Derivatization of Protein Crystals with I3C using Random Microseed Matrix Screening
Published on: January 16, 2021
Novel crystalline phase and first-order phase transitions of human insulin complexed with two distinct phenol
Abstract:
The primary focus of the present work is the study of the effects that two ligands and the crystallization pH have on the crystalline forms of human insulin. For this purpose, human insulin (HI) was co-crystallized with two distinct phenolic derivatives: the organic ligands meta-cresol (m-cresol) and 4-nitrophenol. The formation of polycrystalline precipitates was then followed by means of structural characterization of the individual specimens in terms of unit-cell symmetry and parameters. In both cases, two different polymorphs were identified via X-ray powder diffraction measurements, the first of hexagonal symmetry (R3 space group) at higher pH values and the second of monoclinic symmetry (space group P21) with unit-cell parameters a = 87.4282 (5), b = 70.5020 (3), c = 48.3180 (4) Å, β = 106.8958 (4)°, the latter of which to our knowledge has never been observed before.
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