title: The solution structure of a monomeric insulin. A two-dimensional 1H-NMR study of des-(B26-B30)-insulin in combination with distance geometry and restrained molecular dynamics.
abstract: The solution conformation of des-(B26-B30)-insulin (DPI) has been investigated by 1H-NMR spectroscopy. A set of 250 approximate interproton distance restraints, derived from two-dimensional nuclear Overhauser enhancement spectra, were used as the basis of a structure determination using distance geometry (DG) and distance-bound driven dynamics (DDD). Sixteen DG structures were optimized using energy minimization (EM) and submitted to short 5-ps restrained molecular dynamics (RMD) simulations. A further refinement of the DDD structure with the lowest distance errors was done by energy minimization, a prolonged RMD simulation in vacuo and a time-averaged RMD simulation. An average structure was obtained from a trajectory generated during 20-ps RMD. The final structure was compared with the des-(B26-B30)-insulin crystal structure refined by molecular dynamics and the 2-Zn crystal structure of porcine insulin. This comparison shows that the overall structure of des-(B26-B30)-insulin is retained in solution with respect to the crystal structures with a high flexibility at the N-terminal part of the A chain and at the N-terminal and C-terminal parts of the B chain. In the RMD run a high mobility of Gly A1, Asn A21 and of the side chain of Phe B25 is noticed. One of the conformations adopted by des-(B26-B30)-insulin in solution is similar to that of molecule 1 (Chinese nomenclature) in the crystal structure of porcine insulin.
authors.affiliation: Department of Chemistry, University of Utrecht, The Netherlands.
authors.forename: R M
authors.initials: RM
authors.lastname: Knegtel
authors.forename: R
authors.initials: R
authors.lastname: Boelens
authors.forename: M L
authors.initials: ML
authors.lastname: Ganadu
authors.forename: R
authors.initials: R
authors.lastname: Kaptein
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D007328:Insulin / Q000031:analogs & derivatives* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D013552:Swine; D014961:X-Ray Diffraction
chemical_list: D007328:Insulin; C007285:insulin, despentapeptide(B26-B30)-