This model represents a bacterial family of proteins that may be regulated by SdiA, a member of the LuxR family of transcriptional regulators. The C-terminal domain included in the alignment forms a five-bladed beta-propeller structure. The X-ray structure of Escherichia coli yjiK (C-terminal domain) exhibits binding of calcium ions (Ca++) in what appears to be an evolutionarily conserved site. Sequence analysis suggests a distant relationship to proteins that are characterized as containing NHL-repeats. The latter also form beta-propeller structures, with several examples known to form six-bladed beta-propellers. Several of the six-bladed beta-propellers containing NHL repeats have been characterized functionally, including members with enzymatic functions that are dependent on metal ions. No functional characterization is available for this family of five-bladed propellers, though.
Comment:In the only available X-ray structure, the protein interacts with several calcium ions with what appears to be an evolutionarily conserved site.
Structure:3QQZ: Escherichia coli yjiK binds Ca++ ions via its C-terminal domain, contacts at 4 A
Comment:The site also overlaps with the active site of the structurally similar glycosyl hydrolase families GH32, GH43, GH62, and GH68, when aligned according to matching 3D structure
Jiyao W et al.(2023). "The conserved domain database in 2023.",