UC Merced

Eotaxin belongs to the chemokine family of proteins, which are involved in inflammation and in the development of the immune system, regulating activation and chemotaxis of leukocytes. Chemokines are involved in a variety of inflammatory diseases such as rheumatoid arthritis and allergic asthma. The viral protein CC-chemokine inhibitor (vCCI) from poxviruses can bind many different chemokines with high affinity, which makes it a potentially valuable therapeutic agent to treat such inflammatory diseases. However, it is not clear how vCCI is able to bind so many different chemokines. NMR data from the vCCI:MIP-1β complex and preliminary vCCI:eotaxin NMR data indicates that in eotaxin Phe11, Arg16, Arg 22, Lys 44, and possibly Lys 47 are involved in binding vCCI. Correspondingly, Tyr217, Phe215, Val185, along with Asp141, Glu143 and a flexible acidic loop in vCCI are involved in binding eotaxin. Mutations were made in these residues and binding to vCCI was tested by fluorescence anisotropy. This project investigates the interaction of chemokines and vCCI at a molecular level through NMR, mutagenesis, and fluorescence anisotropy studies. The results of investigation show that residues Phe11, Arg16, Arg 22, Lys 44 in eotaxin are involved in binding vCCI. Single mutations in Asp141, Glu143 of vCCI do not show significant change in binding affinity. More mutations such as a double mutant D141A/E143A vCCI, mutants of other nearby acidic residues (e.g. Asp73, Asp75), need to be done before any conclusion is made.