A novel dimer configuration revealed by the crystal structure at 2.4 Å resolution of human interleukin-5

Abstract

Interleukin-5 (IL-5) is a lineage-specific cytokine for eosinophilpoiesis and plays an important part in diseases associated with increased eosinophils, such as asthma. Human IL-5 is a disulphide-linked homodimer with 115 amino-acid residues in each chain. The crystal structure at 2.4 A resolution reveals a novel two-domain structure, with each domain showing a striking similarity to the cytokine fold found in granulocyte macrophage and macrophage colony-stimulating factors, IL-2 (ref. 5), IL-4 (ref. 6), and human and porcine growth hormones. IL-5 is unique in that each domain requires the participation of two chains. The IL-5 structure consists of two left-handed bundles of four helices laid end to end and two short beta-sheets on opposite sides of the molecule. Surprisingly, the C-terminal strand and helix of one chain complete a bundle of four helices and a beta-sheet with the N-terminal three helices and one strand of the other chain. The structure of IL-5 provides a molecular basis for the design of antagonists and agonists that would delineate receptor recognition determinants critical in signal transduction. This structure determination extends the family of the cytokine bundle of four helices and emphasizes its fundamental significance and versatility in recognizing its receptor.

The GM–CSF/IL‐3/IL‐5 cytokine receptor family: from ligand recognition to initiation of signaling

“…The nuclear magnetic resonance structures of a mutant human IL-3 and murine IL-3 both reveal a four helical bundle topology ( Fig. 2A) very similar to the previously published structures of hGM-CSF and hIL-5 (75,78,86,87,147). Although there is no crystal structure data for the IL-3 receptors, structural studies using homology models based on the GM-CSF receptor and related IL receptor systems, particularly the IL-4 and IL-13 receptors (PDB ID: 3BPO, 3BPN, 3LB6; 85,90), are proving to be very useful.…”

“…Photo crosslinking between IL‐5 and full‐length IL5Rα further confirmed that the crystal structure represented the actual binary complex formed in vivo . The 3‐D structure of IL‐5 in the complex is essentially the same as the previously published structure of the free IL‐5 dimer . Interestingly, the authors report a ‘wrench‐like’ conformation of IL5Rα, similar to distantly related IL13Rα1 and IL13Rα2 receptors when bound to cytokine ( Fig.…”

The GM–CSF/IL‐3/IL‐5 cytokine receptor family: from ligand recognition to initiation of signaling

“…The nuclear magnetic resonance structures of a mutant human IL-3 and murine IL-3 both reveal a four helical bundle topology ( Fig. 2A) very similar to the previously published structures of hGM-CSF and hIL-5 (75,78,86,87,147). Although there is no crystal structure data for the IL-3 receptors, structural studies using homology models based on the GM-CSF receptor and related IL receptor systems, particularly the IL-4 and IL-13 receptors (PDB ID: 3BPO, 3BPN, 3LB6; 85,90), are proving to be very useful.…”

“…Photo crosslinking between IL‐5 and full‐length IL5Rα further confirmed that the crystal structure represented the actual binary complex formed in vivo . The 3‐D structure of IL‐5 in the complex is essentially the same as the previously published structure of the free IL‐5 dimer . Interestingly, the authors report a ‘wrench‐like’ conformation of IL5Rα, similar to distantly related IL13Rα1 and IL13Rα2 receptors when bound to cytokine ( Fig.…”

Analysis of three human interleukin 5 structures suggests a possible receptor binding mechanism

“…The exact stoichiometry of the IL5/IL5R complex on the cell membrane is still unclear. In this paper we describe the detailed comparison of three structures for human IL5 derived from crystallographic data [4, 14]. Based on the observed differences, we propose an induced fit model for IL5 upon receptor binding, which is in agreement with the above mentioned stoichiometry.…”

Epitope Randomization Redefines the Functional Role of Glutamic Acid 110 in Interleukin-5 Receptor Activation

“…5A, the similarity of CD for scIL-5, (wt/A5)scIL-5, (E110W/A5)scIL-5 and (E110W/A6)scIL-5 indicates that the Glu 110 variants likely are folded into secondary structures similar to that of scIL-5. The shapes of the CD spectra are consistent with large ␣-helical contents, consistent with the known structure of IL-5 as a four-helix bundle protein (11). Thermal stabilities of Glu 110 scIL-5 mutants were evaluated by monitoring the effects of increasing temperature on molar ellipticity at 222 nm (Fig.…”

The GM–CSF/IL‐3/IL‐5 cytokine receptor family: from ligand recognition to initiation of signaling

“…The nuclear magnetic resonance structures of a mutant human IL-3 and murine IL-3 both reveal a four helical bundle topology ( Fig. 2A) very similar to the previously published structures of hGM-CSF and hIL-5 (75,78,86,87,147). Although there is no crystal structure data for the IL-3 receptors, structural studies using homology models based on the GM-CSF receptor and related IL receptor systems, particularly the IL-4 and IL-13 receptors (PDB ID: 3BPO, 3BPN, 3LB6; 85,90), are proving to be very useful.…”

“…Photo crosslinking between IL‐5 and full‐length IL5Rα further confirmed that the crystal structure represented the actual binary complex formed in vivo . The 3‐D structure of IL‐5 in the complex is essentially the same as the previously published structure of the free IL‐5 dimer . Interestingly, the authors report a ‘wrench‐like’ conformation of IL5Rα, similar to distantly related IL13Rα1 and IL13Rα2 receptors when bound to cytokine ( Fig.…”

Analysis of three human interleukin 5 structures suggests a possible receptor binding mechanism

“…The exact stoichiometry of the IL5/IL5R complex on the cell membrane is still unclear. In this paper we describe the detailed comparison of three structures for human IL5 derived from crystallographic data [4, 14]. Based on the observed differences, we propose an induced fit model for IL5 upon receptor binding, which is in agreement with the above mentioned stoichiometry.…”

Epitope Randomization Redefines the Functional Role of Glutamic Acid 110 in Interleukin-5 Receptor Activation

“…5A, the similarity of CD for scIL-5, (wt/A5)scIL-5, (E110W/A5)scIL-5 and (E110W/A6)scIL-5 indicates that the Glu 110 variants likely are folded into secondary structures similar to that of scIL-5. The shapes of the CD spectra are consistent with large ␣-helical contents, consistent with the known structure of IL-5 as a four-helix bundle protein (11). Thermal stabilities of Glu 110 scIL-5 mutants were evaluated by monitoring the effects of increasing temperature on molar ellipticity at 222 nm (Fig.…”

The GM–CSF/IL‐3/IL‐5 cytokine receptor family: from ligand recognition to initiation of signaling

“…The nuclear magnetic resonance structures of a mutant human IL-3 and murine IL-3 both reveal a four helical bundle topology ( Fig. 2A) very similar to the previously published structures of hGM-CSF and hIL-5 (75,78,86,87,147). Although there is no crystal structure data for the IL-3 receptors, structural studies using homology models based on the GM-CSF receptor and related IL receptor systems, particularly the IL-4 and IL-13 receptors (PDB ID: 3BPO, 3BPN, 3LB6; 85,90), are proving to be very useful.…”

“…Photo crosslinking between IL‐5 and full‐length IL5Rα further confirmed that the crystal structure represented the actual binary complex formed in vivo . The 3‐D structure of IL‐5 in the complex is essentially the same as the previously published structure of the free IL‐5 dimer . Interestingly, the authors report a ‘wrench‐like’ conformation of IL5Rα, similar to distantly related IL13Rα1 and IL13Rα2 receptors when bound to cytokine ( Fig.…”

Analysis of three human interleukin 5 structures suggests a possible receptor binding mechanism

“…The exact stoichiometry of the IL5/IL5R complex on the cell membrane is still unclear. In this paper we describe the detailed comparison of three structures for human IL5 derived from crystallographic data [4, 14]. Based on the observed differences, we propose an induced fit model for IL5 upon receptor binding, which is in agreement with the above mentioned stoichiometry.…”

Epitope Randomization Redefines the Functional Role of Glutamic Acid 110 in Interleukin-5 Receptor Activation

“…5A, the similarity of CD for scIL-5, (wt/A5)scIL-5, (E110W/A5)scIL-5 and (E110W/A6)scIL-5 indicates that the Glu 110 variants likely are folded into secondary structures similar to that of scIL-5. The shapes of the CD spectra are consistent with large ␣-helical contents, consistent with the known structure of IL-5 as a four-helix bundle protein (11). Thermal stabilities of Glu 110 scIL-5 mutants were evaluated by monitoring the effects of increasing temperature on molar ellipticity at 222 nm (Fig.…”