Chemokine_C, C or lymphotactin subgroup, 1 of 4 subgroup designations of chemokines based on the arrangement of two N-terminal, conserved cysteine residues. Most of the known chemokines (cd00169) belong to either the CC (cd00272) or CXC (cd00273) subclass. The two other subclasses each have a single known member: fractalkine for the CX3C (cd00274) class and lymphotactin for the C (cd00271) class. Chemokine_Cs differ structurally since they contain only one of the two disulfide bridges that are conserved in all other chemokines and they possess a unique C-terminal extension, which is required for biological activity and thought to play a role in receptor binding. Lymphotactin, a mediator of mucosal immunity, has been found to chemoattract neutrophils and B cells through the XCR1 receptor and thought to be a factor in acute allograft rejection and inflammatory bowel disease.
Comment:the N-terminus, N-loop, 30s-loop, and residues next to the disulfides and in the alpha helix are thought to be involved in receptor binding for the family in general
Comment:the C-terminal tail which is unique to lymphotactin is also proposed to play a role in receptor binding
Jiyao W et al.(2023). "The conserved domain database in 2023.",