ISSN:
1399-0047
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
The structures of three R6 human insulin hexamers have been determined. Crystals of monoclinic m-cresol–insulin, monoclinic resorcinol–insulin and rhombohedral m-cresol–insulin diffracted to 1.9, 1.9 and 1.78 Å, respectively, and have been refined to residuals of 0.195, 0.179 and 0.200, respectively. In all three structures, a phenolic derivative is found to occupy the phenolic binding site, where it forms hydrogen bonds to the carbonyl O atom of CysA6 and the N atom of CysA11. Two additional phenolic derivative binding sites were identified within or between hexamers. The structures of all three hexamers are nearly identical, although a large displacement of the N-terminus of one B chain in both monoclinic structures results from coordination to a sodium ion which is located between symmetry-related hexamers. Other minor differences in structure arise from differences in packing in the monoclinic cell compared with the rhombohedral cell. Based upon the differences in conformation of the GluB13 side chains in T6, T3R^{\rm f}_{3} and R6 hexamers, the deprotonation of these side chains appears to be associated with the T→R conformational transition.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0907444900012749
