Direct determination of the interleukin-6 binding epitope of the interleukin-6 receptor by NMR spectroscopy.
All cytokines belonging to the interleukin-6 (IL-6)-type family of cytokines utilize receptors that have a modular build of several immunoglobulin-like and fibronectin type III-like domains. Characteristic of these receptors is a cytokine receptor homology region consisting of two such fibronectin domains defined by a set of four conserved cysteines and a tryptophan-serine-X-tryptophan-serine sequence motif. On target cells, interleukin-6 first binds to its specific receptor and subsequently to a homodimer of the signal transducer protein gp130. The interleukin-6 receptor consists of three extracellular domains. The N-terminal immunoglobulin-like domain is not involved in ligand binding, whereas the third membrane proximal fibronectin-like domain accounts for more than 90% of the binding energy to IL-6. Here, the key residues of this fibronectin-like domain involved in the interaction with IL-6 are described. Chemical shift mapping data with 15N-labeled IL-6R-D3 and unlabeled IL-6 coupled with recent structural data clearly reveal the epitope within the IL-6R-D3 responsible for mediating the high affinity interaction with its cognate cytokine.
Schwantner
Andreas
A
Biochemisches Institut, Christian-Albrechts-Universität Kiel, Olshausenstrasse 40, 24118 Kiel, Germany.
Dingley
Andrew J
AJ
Ozbek
Suat
S
Rose-John
Stefan
S
Grötzinger
Joachim
J
D001665:Binding Sites; D003001:Cloning, Molecular; D017124:Conserved Sequence; D003545:Cysteine; D003903:Deuterium; D004926:Escherichia coli / Q000235:genetics; D015850:Interleukin-6 / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009587:Nitrogen Isotopes; D011487:Protein Conformation; D019947:Receptors, Interleukin-6 / Q000737:chemistry* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism
D015850:Interleukin-6; D009587:Nitrogen Isotopes; D019947:Receptors, Interleukin-6; D011994:Recombinant Proteins; D003903:Deuterium; D003545:Cysteine