second forkhead associated (FHA) domain found in Saccharomyces cerevisiae Serine/threonine-protein kinase RAD53 and similar proteins
RAD53, also called CHEK2 homolog, or serine-protein kinase 1 (Spk1), is a nuclear protein kinase that phosphorylates proteins on serine, threonine, and tyrosine. It controls S-phase checkpoint as well as G1 and G2 DNA damage checkpoints and prevents entry into anaphase and mitotic exit after DNA damage via regulation of the Polo kinase CDC5. It may be involved in the phosphorylation of RPH1. RAD53 contains two FHA domains. This model corresponds to the second one. The FHA domain is a small phosphopeptide recognition module.
Comment: based on structures of other FHA domains with bound phosphopeptide
Comment:GR at the C terminus of strand beta3, SRxH just preceding beta5, and motif SxNG in the beta6-beta7 turn indicate a canonical mode of pThr recognition.
Comment:Conserved residues are involved in binding directly to the ligand backbone and phosphate group. Non-conserved residues may determine binding specificity.