1JCA

Non-standard Design of Unstable Insulin Analogues with Enhanced Activity

1JCA の概要

• エントリーDOI: 10.2210/pdb1jca/pdb
• 関連するPDBエントリー: 1J73
• 分子名称: insulin a, insulin b, ZINC ION, ... (4 entities in total)
• 機能のキーワード: a8-lysine human insulin, insulin receptor, hormone-growth factor complex, hormone/growth factor
• 細胞内の位置: Secreted: P01308 P01308
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 11822.27

構造登録者

Weiss, M.A.,Wan, Z.,Zhao, M.,Chu, Y.-C.,Nakagawa, S.H.,Burke, G.T.,Jia, W.,Hellmich, R.,Katsoyannis, P.G. (登録日: 2001-06-08, 公開日: 2001-06-20, 最終更新日: 2024-10-30)

主引用文献

Weiss, M.A.,Wan, Z.,Zhao, M.,Chu, Y.C.,Nakagawa, S.H.,Burke, G.T.,Jia, W.,Hellmich, R.,Katsoyannis, P.G.
Non-standard insulin design: structure-activity relationships at the periphery of the insulin receptor.
J.Mol.Biol., 315:103-111, 2002

PubMed Abstract: The design of insulin analogues has emphasized stabilization or destabilization of structural elements according to established principles of protein folding. To this end, solvent-exposed side-chains extrinsic to the receptor-binding surface provide convenient sites of modification. An example is provided by an unfavorable helical C-cap (Thr(A8)) whose substitution by favorable amino acids (His(A8) or Arg(A8)) has yielded analogues of improved stability. Remarkably, these analogues also exhibit enhanced activity, suggesting that activity may correlate with stability. Here, we test this hypothesis by substitution of diaminobutyric acid (Dab(A8)), like threonine an amino acid of low helical propensity. The crystal structure of Dab(A8)-insulin is similar to those of native insulin and the related analogue Lys(A8)-insulin. Although no more stable than native insulin, the non-standard analogue is twice as active. Stability and affinity can therefore be uncoupled. To investigate alternative mechanisms by which A8 substitutions enhance activity, multiple substitutions were introduced. Surprisingly, diverse aliphatic, aromatic and polar side-chains enhance receptor binding and biological activity. Because no relationship is observed between activity and helical propensity, we propose that local interactions between the A8 side-chain and an edge of the hormone-receptor interface modulate affinity. Dab(A8)-insulin illustrates the utility of non-standard amino acids in hypothesis-driven protein design.

PubMed: 11779231
DOI: 10.1006/jmbi.2001.5224

実験手法

X-RAY DIFFRACTION (2.5 Å)