Crystallographic and Solution Studies of N-Lithocholyl Insulin: A New Generation of Prolonged-Acting Human Insulins

详细信息    查看全文

• 作者：Jean L. Whittingham ; Ib Jonassen ; Svend Havelund ; Shirley M. Roberts ; Eleanor J. Dodson ; Chandra S. Verma ; Anthony J. Wilkinson ; and G. Guy Dodson
• 刊名：Biochemistry
• 出版年：2004
• 出版时间：May 25, 2004
• 年：2004
• 卷：43
• 期：20
• 页码：5987 - 5995
• 全文大小：411K
• 年卷期：v.43,no.20(May 25, 2004)
• ISSN：1520-4995

文摘

The addition of specific bulky hydrophobic groups to the insulin molecule provides it withaffinity for circulating serum albumin and enables it to form soluble macromolecular complexes at thesite of subcutaneous injection, thereby securing slow absorption of the insulin analogue into the bloodstream and prolonging its half-life once there. N-Lithocholic acid acylated insulin [Lys^B29-lithocholyldes-(B30) human insulin] has been crystallized and the structure determined by X-ray crystallography at1.6 Å resolution to explore the molecular basis of its assembly. The unit cell in the crystal consists of aninsulin hexamer containing two zinc ions, with two m-cresol molecules bound at each dimer-dimer interfacestabilizing an R₆ conformation. Six covalently bound lithocholyl groups are arranged symmetrically aroundthe outside of the hexamer. These form specific van der Waals and hydrogen-bonding interactions at theinterfaces between neighboring hexamers, possibly representing the kinds of interactions which occur inthe soluble aggregates at the site of injection. Comparison with an equivalent nonderivatized native insulinhexamer shows that the addition of the lithocholyl group disrupts neither the important conformationalfeatures of the insulin molecule nor its hexamer-forming ability. Indeed, binding studies show that theaffinity of N-lithocholyl insulin for the human insulin receptor is not significantly diminished.