The LIM domain of N-RAP: N-RAP is a muscle-specific protein concentrated at myotendinous junctions in skeletal muscle and intercalated disks in cardiac muscle. LIM domain is found at the N-terminus of N-RAP and the C-terminal of N-RAP contains a region with multiple of nebulin repeats. N-RAP functions as a scaffolding protein that organizes alpha-actinin and actin into symmetrical I-Z-I structures in developing myofibrils. Nebulin repeat is known as actin binding domain. The N-RAP is hypothesized to form antiparallel dimerization via its LIM domain. As in other LIM domains, this domain family is 50-60 amino acids in size and shares two characteristic zinc finger motifs. The two zinc fingers contain eight conserved residues, mostly cysteines and histidines, which coordinately bond to two zinc atoms. LIM domains function as adaptors or scaffolds to support the assembly of multimeric protein.
Comment:The two zinc fingers contain eight conserved residues, mostly cysteines and histidines, which coordinately bond to two zinc atoms. The Zn binding residues of LIM domain are highly conserved.
Jiyao W et al.(2023). "The conserved domain database in 2023.",