Secondary structure determination of 15N‐labelled human Long‐[Arg‐3]‐insulin‐like growth factor 1 by multidimensional NMR spectroscopy

FEBS Letters

Carver, John A⁴  Keniry, Max A³  Laajoki, Leanne G³  Shooter, Gary K¹  Wallace, John C¹  Francis, Geoffrey L²  Le Breton, Eugene⁴ 

[1] Department of Biochemistry, University of Adelaide, Adelaide, South Australia 5000, Australia;CSIRO Division of Human Nutrition and CRC for Tissue Growth and Repair, P.O. Box 10065, Adelaide, South Australia 5000, Australia;Research School of Chemistry, The Australian National University, GPO Box 414, Canberra, ACT 2601, Australia;Department of Chemistry, University of Wollongong, Wollongong, NSW 2522, Australia

关键词: 1H NMR;    IGF-I;    Growth factor;    Protein structure;    HMQC;    heteronuclear multiple quantum correlation;    HSQC;    heteronuclear single quantum correlation;    IGF-I;    insulin-like growth factor 1;    IGF-II;    insulin-like growth factor 2;    IGFBPs;    insulin-like growth factor binding proteins;    NMR;    nuclear magnetic resonance;    NOESY;    nuclear Overhauser effect spectroscopy;    TOCSY;    total correlation spectroscopy;   

DOI  :  10.1016/S0014-5793(97)01496-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Insulin-like growth factors (IGFs) are a group of proteins that promote cell growth and differentiation. Long-[Arg-3]-IGF-I (Francis et al. (1992) J. Mol. Endocrinol. 8, 213–223), a potent analogue of IGF-I, which has a Glu-3 to Arg-3 substitution and a hydrophobic, thirteen amino acid N-terminal extension, has been studied by ¹H,¹⁵N NMR spectroscopy. All the backbone ¹H and ¹⁵N assignments and most of the ¹H sidechain assignments have been completed. The secondary structure elements were identified by determining the sequential and medium range NOEs from sensitivity-enhanced ¹⁵N-NOESY-HSQC and sensitivity-enhanced ¹⁵N-HSQC-NOESY-HSQC spectra. The IGF-I domain of Long-[Arg-3]-IGF-I was found to have an almost identical structure to IGF-I. The N-terminal seven amino acid residues of the extension have very few medium range or long range NOEs but the next five amino acids form a turn-like structure that is spatially close to the beginning of helix 1 in the IGF-I domain. Hydrogen-deuterium exchange experiments show that all the slowly exchanging backbone amide protons in the IGF-I domain are either in the helical or the extended structural elements. Many of the amide protons in the N-terminal extension are also protected from the solvent although the residues in this part of the extension do not have any identifiable secondary structure. The results are interpreted in terms of the increased biological potency of Long-[Arg-3]-IGF-I and the decreased binding to insulin-like growth factor binding proteins.

【 授权许可】

Unknown