Download MendeleyStructural basis for Ca(2+)-induced activation of human PAD4
Arita, K., Hashimoto, H., Shimizu, T., Nakashima, K., Yamada, M., Sato, M.(2004) Nat Struct Mol Biol 11: 777-783
- PubMed: 15247907
- DOI: https://doi.org/10.1038/nsmb799
- Primary Citation of Related Structures:
1WD8, 1WD9, 1WDA - PubMed Abstract:
Peptidylarginine deiminase 4 (PAD4) is a Ca(2+)-dependent enzyme that catalyzes the conversion of protein arginine residues to citrulline. Its gene is a susceptibility locus for rheumatoid arthritis. Here we present the crystal structure of Ca(2+)-free wild-type PAD4, which shows that the polypeptide chain adopts an elongated fold in which the N-terminal domain forms two immunoglobulin-like subdomains, and the C-terminal domain forms an alpha/beta propeller structure. Five Ca(2+)-binding sites, none of which adopt an EF-hand motif, were identified in the structure of a Ca(2+)-bound inactive mutant with and without bound substrate. These structural data indicate that Ca(2+) binding induces conformational changes that generate the active site cleft. Our findings identify a novel mechanism for enzyme activation by Ca(2+) ions, and are important for understanding the mechanism of protein citrullination and for developing PAD-inhibiting drugs for the treatment of rheumatoid arthritis.
Organizational Affiliation:
Graduate School of Integrated Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan.
