Soluble LDL minireceptors - Minimal structure requirements for recognitionof minor group human rhinovirus

Soluble human low density lipoprotein minireceptors with less than seven li gand binding repeats las are present in the native membrane receptor) were expressed in Sf9 insect cells with a hexa-His tag fused to the C terminus. The recombinant truncated proteins were affinity purified from the tissue c ulture supernatants by Ni-NTA column chromatography. Minireceptors with mor e than two repeats bound to rabbit beta very low density lipoprotein and co uld thus be further purified by affinity chromatography. Binding and cell p rotection assays indicated that two ligand binding repeats are sufficient f or attachment of minor group human rhinoviruses to immobilized receptors, w hereas at least three ligand binding repeats are required to protect HeLa c ells against viral infection.