forkhead associated (FHA) domain found in Chlamydia trachomatis Ct664 protein and similar proteins
This subfamily corresponds to a group of uncharacterized FHA domain-containing proteins which show high sequence similarity with Chlamydia trachomatis Ct664 protein. Ct664 situates within the type III secretion system cluster that also encodes an STPK (CT673 in C. trachomatis), suggesting a role of CT664 in the chlamydial type III secretion system by mediating phosphorylation-dependent protein-protein interactions. The FHA domain is a small phosphopeptide recognition module.
Feature 1:putative phosphopeptide binding site [polypeptide binding site]
Evidence:
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.
Structure:3GQS: Chlamydia trachomatis CT664 protein FHA domain binds phosphate at the phosphopeptide binding site; contacts at 4A
Jiyao W et al.(2023). "The conserved domain database in 2023.",