Semisynthesis of an evasin from tick saliva reveals a critical role of tyrosine sulfation for chemokine binding and inhibition

Significance A hallmark of numerous inflammatory diseases is the overexpression of chemokines giving rise to inappropriate leukocyte recruitment. The inhibition of chemokines is therefore recognized as an attractive strategy for the development of antiinflammatories. Blood-feeding ticks produce sulfated proteins called “evasins” in their saliva that modulate the host inflammatory response by binding to host chemokines. In this work we employ a semisynthetic approach to generate variants of the ACA-01 evasin from theAmblyomma cajennense tick bearing homogeneous sulfation patterns. We reveal that sulfation significantly enhances chemokine binding as well as chemokine receptor inhibition. Our work lays the foundation for the development of engineered sulfopeptides and sulfoproteins to target a range of inflammatory diseases associated with dysregulated chemokine-receptor signaling.