title: Crystal structure of human recombinant interleukin-4 at 2.25 A resolution.
abstract: The crystal structure of human recombinant interleukin-4 (IL-4) has been solved by multiple isomorphous replacement, and refined to an R factor of 0.218 at 2.25 A resolution. The molecule is a left-handed four-helix bundle with a short stretch of beta sheet. The structure bears close resemblance to other cytokines such as granulocyte-macrophage colony stimulating factor (GM-CSF). Although no sequence similarity of IL-4 to GM-CSF and other related cytokines has been previously postulated, structure-based alignment of IL-4 and GM-CSF revealed that the core of the molecules, including large parts of all four helices and extending over half of the molecule, has 30% sequence identity. This may have identified regions which are not only important to maintain structure, but could also play a role in receptor binding.
authors.affiliation: Macromolucar Structure Laboratory, NCI-Fredrick Cancer Research and Development Center, MD 21702.
authors.forename: A
authors.initials: A
authors.lastname: Wlodawer
authors.forename: A
authors.initials: A
authors.lastname: Wlodaver
authors.forename: A
authors.initials: A
authors.lastname: Pavlovsky
authors.forename: A
authors.initials: A
authors.lastname: Gustchina
mesh_terms: D000595:Amino Acid Sequence; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000737:chemistry; D006801:Humans; D015847:Interleukin-4 / Q000737:chemistry*; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry; D012984:Software; D014961:X-Ray Diffraction / Q000379:methods
chemical_list: D011994:Recombinant Proteins; D015847:Interleukin-4; D016178:Granulocyte-Macrophage Colony-Stimulating Factor