Crystallization and preliminary X-ray studies of thymus and activation-regulated chemokine (TARC)

Thymus and activation-regulated chemokine (TARC) is a CC chemokine that is most highly expressed in the thymus. TARC interacts primarily with the CCR4 receptor and to a lesser extent with the CCR8 receptor. Three different crystal forms of synthetically prepared TARC were grown in triclinic, hexagonal and tetragonal systems. The X-ray data for the triclinic crystals (unit-cell parameters a = 56.46, b = 76.48, c = 88.37 Å, α = 85.8, β = 72.8, γ = 70.0°) extend to 1.85 Å on a conventional radiation source. The hexagonal crystals diffracted to 2.2 Å at a synchrotron-radiation source and belong to either space group P6₁22 or P6₅22, with unit-cell parameters a = 61.8, c = 315. Å. The tetragonal crystals diffracted to about 5 Å at a synchrotron-radiation source and had approximate unit-cell parameters a = b = 47.7, c = 58.2 Å.