Immunological implications of a structural analysis of two different porcine IL1β proteins expressed in macrophages and embryos

IL1β is an important protein in vertebrates. It is a member of the cytokine protein family and is involved in generating an inflammatory response to infections. Researchers have found that there are two porcine IL1β proteins expressed - one in embryos and the other in macrophage and endometrial tissues. These two proteins have about 86% sequence identity. In this paper, we attempt to describe how these two proteins might differ structurally and functionally. We find that 1) A predicted binding site appears to have different side chain arrangements that might lead to different binding efficiencies for the same protein or even to different partners. 2) The Caspase 1 cleavage site in the precursor proteins differs in a way that has previously been experimentally determined to reduce the cleavage activity by one order of magnitude for the embryonic IL1β, conferring a significant advantage to the protein (embryonic IL1β).

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