Determination of the Secondary Structure and Folding Topology of Human Interleukin-4 Using Three-Dimensional Heteronuclear Magnetic Resonance Spectroscopy

Authors

Daniel S. Garrett, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health
Robert Powers, University of Nebraska - LincolnFollow
Carl J. March, Immunex Corporation, 51 University Street, Seattle, Washington
Eric A. Frieden, Immunex Corporation, 51 University Street, Seattle, Washington
G. Marius Clore, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health
Angela M. Gronenborn, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health

Date of this Version

1992

Citation

Biochemistry 1992, 31, 4347-4353

Comments

U.S. Government Work

Abstract

The secondary structure of human recombinant interleukin-4 (IL-4) has been investigated by three-dimensional (3D) ¹⁵N- and ¹³C-edited nuclear Overhauser (NOE) spectroscopy on the basis of the ¹H, ¹⁵N, and ¹³C assignments presented in the preceding paper [Powers, R., Garrett, D. S., March, C. J., Frieden, E. A,, Gronenborn, A. M., & Clore, G. M. (1992) Biochemistry (preceding paper in this issue)]. Based on the NOE data involving the NH, C^αH, and C^βH protons, as well as ³J_HNα coupling constant, amide exchange, and ¹³C^α and ¹³C^β secondary chemical shift data, it is shown that IL-4 consists of four long helices (residues 9-21, 45-64, 74-96, and 113-129), two small helical turns (residues 27-29 and 67-70), and a mini antiparallel β-sheet (residues 32-34 and 110-1 12). In addition, the topological arrangement of the helices and the global fold could be readily deduced from a number of long-range interhelical NOEs identified in the 3D ¹³C-edited NOE spectrum in combination with the spatial restrictions imposed by three disulfide bridges. These data indicate that the helices of interleukin-4 are arranged in a left-handed four-helix bundle with two overhand connections.