In molecular biology, the LCCL domain is a protein domain which has been named after several well-characterised proteins that were found to contain it, namely Limulus clotting factor C, Cochlin (Coch-5b2) and Lgl1 (CRISPLD2). It is an about 100 amino acids domain whose C-terminal part contains a highly conserved histidine in a conservedmotif YxxxSxxCxAAVHxGVI. The LCCL module is thought to be an autonomouslyfolding domain that has been used for the construction of various modular proteins through exon-shuffling. It has been found in various metazoanproteins in association with , C-type lectin domains, , CUB domains, or CAP domains. It has been proposed that the LCCL domain could be involved in lipopolysaccharide (LPS) binding.[1][2] LCCL exhibits a novel fold.[3]
Some proteins known to contain a LCCL domain include Limulus factor C, an LPS endotoxin-sensitive trypsin type serine protease which serves to protect the organism from bacterial infection; vertebratecochlear protein cochlin or coch-5b2 (Cochlin is probably a secreted protein, mutations affecting the LCCL domain of coch-5b2 cause the deafness disorder DFNA9 in humans); and mammalian late gestationlung protein Lgl1, contains two tandem copies of the LCCL domain.[4]