Identification of the domain in the human interleukin-11 receptor that mediates ligand binding.
The interleukin-11 receptor (IL-11R) belongs to the hematopoietic receptor superfamily. The functional receptor complex comprises IL-11, IL-11R and the signal-transducing subunit gp130. The extracellular part of the IL-11R consists of three domains: an N-terminal immunoglobulin-like domain, D1, and two fibronectin-type III-like (FNIII) domains and D2 and D3. The two FNIII domains comprise the cytokine receptor-homology region defined by a set of four conserved cysteine residues in the N-terminal domain (D2) and a WSXWS sequence motif in the C-terminal domain (D3). We investigated the structural and functional role of the third extracellular receptor domain of IL-11R. A molecular model of the human IL-11/IL-11R complex allowed the identification of amino acid residues in IL-11R to be involved in ligand binding. Most of them were located in the third extracellular domain, which therefore should be able to bind with high affinity to IL-11. To prove this prediction, domain D3 of the IL-11R was expressed in Escherichia coli, refolded and purified. For structural characterization, circular dichroism, fluorescence and NMR spectroscopy were used. By plasmon resonance experiments, we show that the ligand-binding capacity of this domain is as high as that one for the whole receptor. These results provide a basis for further structural investigations that could be used for the rational design of potential agonists and antagonists essential in human therapy.
Institut für Biochemie RWTH-Aachen, Universitätsklinikum, Pauwelsstr.30, Aachen, 52057, Germany.
K
K
Schleinkofer
A
A
Dingley
I
I
Tacken
M
M
Federwisch
G
G
Müller-Newen
P C
PC
Heinrich
P
P
Vusio
Y
Y
Jacques
J
J
Grötzinger
D000595:Amino Acid Sequence; D002942:Circular Dichroism; D017124:Conserved Sequence; D003545:Cysteine / Q000378:metabolism; D005454:Fluorescence Polarization; D006801:Humans; D053703:Interleukin-11 Receptor alpha Subunit; D007700:Kinetics; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011489:Protein Denaturation; D017510:Protein Folding; D020673:Protein Renaturation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D018123:Receptors, Interleukin / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D053702:Receptors, Interleukin-11; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D016415:Sequence Alignment; D020349:Surface Plasmon Resonance; D013696:Temperature; D013816:Thermodynamics
C508428:IL11RA protein, human; D053703:Interleukin-11 Receptor alpha Subunit; D008024:Ligands; D018123:Receptors, Interleukin; D053702:Receptors, Interleukin-11; D011994:Recombinant Proteins; D003545:Cysteine