Secondary structure and topology of human interleukin 4 in solution.
Human interleukin 4 (IL-4) has been studied by 2D and 3D NMR techniques using uniformly 15N-labeled recombinant protein. Assignment of resonances for all but 3 of the 130 residues of the recombinant protein has been achieved, enabling the secondary structure of the protein to be defined. This consists of four major alpha-helical regions and one short section of double-stranded antiparallel beta-sheet. Analysis of distance and angle restraints derived from NMR experiments has enabled the overall molecular topology to be determined. This is related to that found for other four-helix proteins but has several distinctive features including cross-linking of helices by means of three disulfide bonds and a short section of beta-sheet. The structural analysis gives support to the hypothesis that many helical cytokines have a common fold and provides a basis for understanding the biological function of IL-4.
Inorganic Chemistry Laboratory, University of Oxford, England.
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C
Redfield
L J
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Smith
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J
Boyd
G M
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Lawrence
R G
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Edwards
R A
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Smith
C M
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Dobson
D000595:Amino Acid Sequence; D003432:Cross-Linking Reagents; D006801:Humans; D015847:Interleukin-4 / Q000737:chemistry* / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry; D012996:Solutions
D003432:Cross-Linking Reagents; D011994:Recombinant Proteins; D012996:Solutions; D015847:Interleukin-4