High affinity insulin binding by soluble insulin receptor extracellular domain fused to a leucine zipper

FEBS Letters

Bentley, John D.¹  Cosgrove, Leah J.¹  Elleman, Thomas C.¹  McKern, Neil M.¹  Ivancic, Neva¹  Ward, Colin W.¹  Hoyne, Peter A.¹ 

[1] CSIRO, Division of Health Sciences and Nutrition, 343 Royal Parade, Parkville, Vic. 3052, Australia

关键词: Insulin receptor;    Leucine zipper;    Ectodomain chimera;    Expression;    High affinity binding;   

DOI  :  10.1016/S0014-5793(00)01872-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Insulin receptors (IRs) that are truncated at the end of the ectodomain form dimers that bind insulin with different characteristics to wild type receptors. These soluble IRs have lowered affinity for insulin compared with full-length IR, and exhibit linear Scatchard plots in contrast to the curvilinear plots obtained with full-length IR, IR truncated at the C-terminus of the transmembrane region and IR ectodomains fused to the self-associating constant domains from Fc or λ immunoglobulins. In this report, we have fused the IR ectodomain to the 33 residue leucine zipper from the transcriptional activator GCN4 of Saccharomyces cerevisiae. This fusion protein binds insulin with high affinity in a manner comparable to native receptor. The respective dissociation constants were K _d1 8.2×10⁻¹¹ M and K _d2 1.6×10⁻⁸ M for hIRedZip and K _d1 5.7×10⁻¹¹ M and K _d2 6.3×10⁻⁹ M for membrane-anchored, native receptor.

【 授权许可】

Unknown