WAP Four Disulfide Core Domain Protein 5 (WFDC5)

WFDC5 encodes a member of the WAP-type four-disulfide core (WFDC) domain family. Most WFDC proteins contain only one WFDC domain, and this encoded protein contains two WFDC domains. The WFDC domain, or WAP signature motif, contains eight cysteines forming four disulfide bonds at the core of the protein, and functions as a protease inhibitor. Most WFDC gene members are localized to chromosome 20q12-q13 in two clusters: centromeric and telomeric. The deduced 123-amino acid protein contains an N-terminal signal peptide, followed by 2 WAP domains. Each WAP domain contains 8 cysteines that form conserved disulfide bridges, and each WAP domain forms a proposed protease-binding loop and a beta sheet. The mature 99-amino acid WAP1 protein has a calculated molecular mass of 10.9 kD.