The crystal structure of desheptapeptide (B24-B30) insulin (DHPI), a virtually inactive analog of insulin, was determined at 1.6 A resolution. In the refined structure model, DHPI retains three alpha-helices (A1-A8, A12-A18, and B9-B19) as its structural framework, while great conformational changes occur in the N and C termini of B-chain ...
The crystal structure of desheptapeptide (B24-B30) insulin (DHPI), a virtually inactive analog of insulin, was determined at 1.6 A resolution. In the refined structure model, DHPI retains three alpha-helices (A1-A8, A12-A18, and B9-B19) as its structural framework, while great conformational changes occur in the N and C termini of B-chain. The beta-turn, which lies in B20-B30 in insulin and insulin analogs with high potency, no longer exists in DHPI. Relative motion is observed among the three alpha-helices, each as a rigid functional group. In contrast, a region covering B5-B6 and A6-A11 exhibits a relatively stable conformation. We interpret our results as identifying: (i) the importance of beta-turn in determining the receptor-binding potency of insulin and (ii) a leading role of PheB24 in maintaining the beta-turn structure.
Related Citations:
Refinement of the Structure of Despentapeptide (B26-B30) Insulin at 1.5 Angstroms Resolution Dai, J.B., Lou, M.Z., You, J.M., Liang, D.C. (1987) Sci Sin B 30: 55
Crystallographic Studies on Desheptapeptide(B24-B30) Insulin-Growth of Single Crystals and Determination of its Crystallographic Parameters Chang, W.R., Xie, D.L., Liang, D.C., al., et (1982) Sci Sin B 25: 385
Organizational Affiliation:
National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing.
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