Members of the inhibitor of apoptosis (IAP) family of proteins are able
to inhibit cell death following viral infection, during development or in
cell lines in vitro. All IAP proteins bear one or more baculoviral
IAP repeats (BIRs). Here we describe the solution structure of the third BIR
domain from the mammalian IAP homolog B (MIHB /c- IAP-1). The BIR domain has
a novel fold that is stabilized by zinc tetrahedrally coordinated by one histidine
and three cysteine residues. The structure consists of a series of short -helices
and turns with the zinc packed in an unusually hydrophobic environment created
by residues that are highly conserved among all BIRs.
-helices
and turns with the zinc packed in an unusually hydrophobic environment created
by residues that are highly conserved among all BIRs.
