1KMF

NMR STRUCTURE OF HUMAN INSULIN MUTANT ILE-A2-ALLO-ILE, HIS-B10-ASP, PRO-B28-LYS, LYS-B29-PRO, 15 STRUCTURES

Summary for 1KMF

• Entry DOI: 10.2210/pdb1kmf/pdb
• Related: 1K3M
• NMR Information: BMRB: 5246
• Descriptor: Insulin (2 entities in total)
• Functional Keywords: hormone, human insulin, mutant, hormone-growth factor complex, hormone/growth factor
• Cellular location: Secreted: P01308 P01308
• Total number of polymer chains: 2
• Total formula weight: 5794.59

Authors

Xu, B.,Hua, Q.X.,Nakagawa, S.H.,Jia, W.,Chu, Y.C.,Katsoyannis, P.G.,Weiss, M.A. (deposition date: 2001-12-14, release date: 2002-01-09, Last modification date: 2021-10-27)

Primary citation

Xu, B.,Hua, Q.X.,Nakagawa, S.H.,Jia, W.,Chu, Y.C.,Katsoyannis, P.G.,Weiss, M.A.
Chiral mutagenesis of insulin's hidden receptor-binding surface: structure of an allo-isoleucine(A2) analogue.
J.Mol.Biol., 316:435-441, 2002

PubMed Abstract: The hydrophobic core of vertebrate insulins contains an invariant isoleucine residue at position A2. Lack of variation may reflect this side-chain's dual contribution to structure and function: Ile(A2) is proposed both to stabilize the A1-A8 alpha-helix and to contribute to a "hidden" functional surface exposed on receptor binding. Substitution of Ile(A2) by alanine results in segmental unfolding of the A1-A8 alpha-helix, lower thermodynamic stability and impaired receptor binding. Such a spectrum of perturbations, although of biophysical interest, confounds interpretation of structure-activity relationships. To investigate the specific contribution of Ile(A2) to insulin's functional surface, we have employed non-standard mutagenesis: inversion of side-chain chirality in engineered monomer allo-Ile(A2)-DKP-insulin. Although the analogue retains native structure and stability, its affinity for the insulin receptor is impaired by 50-fold. Thus, whereas insulin's core readily accommodates allo-isoleucine at A2, its activity is exquisitely sensitive to chiral inversion. We propose that the Ile(A2) side-chain inserts within a chiral pocket of the receptor as part of insulin's hidden functional surface.

PubMed: 11866509
DOI: 10.1006/jmbi.2001.5377

Experimental method

SOLUTION NMR