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

• Published in: European journal of biochemistry Vol. 202; no. 2; pp. 447 - 458
• Main Authors: KNEGTEL, R. M. A, BOELENS, R, GANADU, M. L, KAPTEIN, R
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell 05-12-1991
• Subjects: Amino Acid Sequence; Animals; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Insulin - analogs & derivatives; Insulin - chemistry; Magnetic Resonance Spectroscopy; Models, Molecular; Molecular biophysics; Molecular Sequence Data; Protein Conformation; Spectroscopy : techniques and spectras; Swine; X-Ray Diffraction; Protein hormone; Overhauser effect; Mobility; Primary structure; NMR spectrometry; Insulin; Spatial structure; Conformation; Two dimension spectrometry
• ISSN: 0014-2956; 1432-1033

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.