text: A structural feature common to all IAP family proteins is that they all contain at least one baculoviral IAP repeat (BIR) domain characterized by a conserved zinc-coordinating Cys/His motif at the N-terminal half of the protein.
  Survivin is distinguished from other IAP family members in that it has only one BIR domain. The mice and human BIR domain of survivin are very similar structurally except for two differences that may affect function variability. The human survivin also contains an elongated C-terminal helix comprising 42 amino acids. Survivin is 16.5 kDa large and is the smallest member of the IAP family.
  X-ray crystallography has shown two molecules of human survivin coming together to form a bowtie-shape dimer through a hydrophobic interface. This interface includes N-terminal residues 6-10 just before the BIR domain region and the 10 residue region connecting the BIR domain to the C-terminal helix. The structural integrity of the determined crystal structure of survivin is quite reliable, as physiological conditions were used to obtain the images.