title: Solution structure of the human CC chemokine 2: A monomeric representative of the CC chemokine subtype.
abstract: HCC-2, a 66-amino acid residue human CC chemokine, was reported to induce chemotaxis on monocytes, T-lymphocytes, and eosinophils. The three-dimensional structure of HCC-2 has been determined by 1H nuclear magnetic resonance (NMR) spectroscopy and restrained molecular dynamics calculations on the basis of 871 experimental restraints. The structure is well-defined, exhibiting average root-mean-square deviations of 0.58 and 0.96 A for the backbone heavy atoms and all heavy atoms of residues 5-63, respectively. In contrast to most other chemokines, subtle structural differences impede dimer formation of HCC-2 in a concentration range of 0.1 microM to 2 mM. HCC-2, however, exhibits the same structural elements as the other chemokines, i.e., a triple-stranded antiparallel beta-sheet covered by an alpha-helix, showing that the chemokine fold is not influenced by quaternary interactions. Structural investigations with a HCC-2 mutant prove that a third additional disulfide bond present in wild-type HCC-2 is not necessary for maintaining the relative orientation of the helix and the beta-sheet.
mesh_terms: D000595:Amino Acid Sequence; D018925:Chemokines / Q000737:chemistry; D019742:Chemokines, CC / Q000737:chemistry*; D002845:Chromatography; D003545:Cysteine / Q000737:chemistry; D004220:Disulfides / Q000737:chemistry*; D006801:Humans; D019402:Macrophage Inflammatory Proteins; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015846:Monokines; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid