Cdc25 phosphatases activate the cell division kinases throughout the cell cycle. The 2.3 A structure of the human Cdc25A catalytic domain reveals a small alpha/beta domain with a fold unlike previously described phosphatase structures but identical to rhodanese, a sulfur-transfer protein. Only the active-site loop, containing the Cys-(X)5-Arg motif, shows similarity to the tyrosine phosphatases. In some crystals, the catalytic Cys-430 forms a disulfide bond with the invariant Cys-384, suggesting that Cdc25 may be self-inhibited during oxidative stress. Asp-383, previously proposed to be the general acid, instead serves a structural role, forming a conserved buried salt-bridge. We propose that Glu-431 may act as a general acid. Structure-based alignments suggest that the noncatalytic domain of the MAP kinase phosphatases will share this topology, as will ACR2, a eukaryotic arsenical resistance protein.

• PMID: 9604936
• DOI full text
• PubMed

Reference Type

Journal Article | Research Support, Non-U.S. Gov't | Research Support, U.S. Gov't, P.H.S.

Authors

Fauman EB, Cogswell JP, Lovejoy B, Rocque WJ, Holmes W, Montana VG, Piwnica-Worms H, Rink MJ, Saper MA

Primary Lit For

Additional Lit For

Review For