Novel crystalline phase and first‐order phase transitions of human insulin complexed with two distinct phenol derivatives. (1st April 2015)

• Record Type: Journal Article
• Authors: Valmas, A.; Magiouf, K.; Fili, S.; Norrman, M.; Schluckebier, G.; Beckers, D.; Degen, T.; Wright, J.; Fitch, A.; Gozzo, F.; Giannopoulou, A. E.; Karavassili, F.; Margiolaki, I.
• Is Part Of: Acta crystallographica. Volume 71:Part 4(2015:Apr.)
• Page Start: 819
• Page End: 828
• Publication Date: 2015-04-01
• Subjects: Biomolecules -- Structure -- Periodicals; Physical biochemistry -- Periodicals; X-ray crystallography -- Periodicals; Crystallography -- Periodicals; 572
• DOI: 10.1107/S1399004715001376
• Languages: English
• ISSNs: 0907-4449

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>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 <italic>meta</italic>‐cresol (<italic>m</italic>‐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 <italic>via</italic> X‐ray powder diffraction measurements, the first of hexagonal symmetry (<italic>R</italic>3 space group) at higher pH values and the second of monoclinic symmetry (space group <italic>P</italic>2₁) with unit‐cell parameters <italic>a</italic> = 87.4282 (5), <italic>b</italic> = 70.5020 (3), <italic>c</italic> = 48.3180 (4) Å, β = 106.8958 (4)°, the latter of which to our knowledge has never been observed before.</p> </abstract>