Crystal structure of allo-Ile(A2)-insulin, an inactive chiral analogue: implications for the mechanism of receptor binding.Wan, Z.L., Xu, B., Chu, Y.C., Katsoyannis, P.G., Weiss, M.A.
(2003) Biochemistry 42: 12770-12783
- PubMed: 14596591
- DOI: 10.1021/bi034430o
- Primary Citation of Related Structures:
- PubMed Abstract:
- CHIRAL MUTAGENESIS OF INSULIN'S HIDDEN
RECEPTOR-BINDING SURFACE: STRUCTURE OF AN
ALLO-ISOLEUCINE (A2) ANALOGUE
Xu, B., Hua, Q.X., NAKAGAWA, S.H., JIA, W., CHU, Y.C., KASOYANNIS, P.G., WEISS, M.A.
(2002) J Mol Biol 316: 435
- A CAVITY-FORMING MUTATION IN INSULIN INDUCES
SEGMENTAL UNFOLDING OF A SURROUNDING ALPHA-HELIX
XU, B., HUA, Q.X., NAKAGAWA, S.H., JIA, W., CHU, Y.C., KATSOYANNIS, P.G., WEISS, M.A.
(2002) Protein Sci 11: 104
- NON-STANDARD INSULIN DESIGN: STRUCTURE-ACTIVITY
RELATIONSHIPS AT THE PERIPHERY OF THE INSULIN Receptor
WEISS, M.A., WAN, Z., ZHAO, M., CHU, Y.C., NAKAGAWA, S.H., BURKE, G.T., JIA, W., HELLMICH, R., KATSOYANNIS, P.G.
(2002) J Mol Biol 315: 103
- IS PROTEIN FOLDING HIERARCHIC? I. LOCAL STRUCTURE
AND PEPTIDE FOLDING
BALDWIN, R.L., ROSE, G.D.
(1999) Trends Biochem Sci 24: 26
- IS PROTEIN FOLDING HIERARCHIC? II. FOLDING
INTERMEDIATES AND TRANSITION STATES
BALDWIN, R.L., ROSE, G.D.
(1999) Trends Biochem Sci 24: 77
The crystal structure of an inactive chiral analogue of insulin containing nonstandard substitution allo-Ile(A2) is described at 2.0 A resolution. In native insulin, the invariant Ile(A2) side chain anchors the N-terminal alpha-helix of the A-chain to the hydrophobic core ...
The crystal structure of an inactive chiral analogue of insulin containing nonstandard substitution allo-Ile(A2) is described at 2.0 A resolution. In native insulin, the invariant Ile(A2) side chain anchors the N-terminal alpha-helix of the A-chain to the hydrophobic core. The structure of the variant protein was determined by molecular replacement as a T(3)R(3) zinc hexamer. Whereas respective T- and R-state main-chain structures are similar to those of native insulin (main-chain root-mean-square deviations (RMSD) of 0.45 and 0.54 A, respectively), differences in core packing are observed near the variant side chain. The R-state core resembles that of the native R-state with a local inversion of A2 orientation (core side chain RMSD 0.75 A excluding A2); in the T-state, allo-Ile(A2) exhibits an altered conformation in association with the reorganization of the surrounding side chains (RMSD 0.98 A). Surprisingly, the core of the R-state is similar to that observed in solution nuclear magnetic resonance (NMR) studies of an engineered T-like monomer containing the same chiral substitution (allo-Ile(A2)-DKP-insulin; Xu, B., Hua, Q. X., Nakagawa, S. H., Jia, W., Chu, Y. C., Katsoyannis, P. G., and Weiss, M. A. (2002) J. Mol. Biol. 316, 435-441). Simulation of NOESY spectra based on crystallographic protomers enables the analysis of similarities and differences in solution. The different responses of the T- and R-state cores to chiral perturbation illustrates both their intrinsic plasticity and constraints imposed by hexamer assembly. Although variant T- and R-protomers retain nativelike protein surfaces, the receptor-binding activity of allo-Ile(A2)-insulin is low (2% relative to native insulin). This seeming paradox suggests that insulin undergoes a change in conformation to expose Ile(A2) at the hormone-receptor interface.
Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, USA.