Leucine-rich repeats are frequently involved in the formation of protein–protein interactions.[3][4]
Examples
Leucine-rich repeat motifs have been identified in a large number of functionally unrelated proteins.[5] The best-known example is the ribonuclease inhibitor, but other proteins such as the tropomyosin regulator tropomodulin and the toll-like receptor also share the motif. In fact, the toll-like receptor possesses 10 successive LRR motifs which serve to bind pathogen- and danger-associated molecular patterns.
Although the canonical LRR protein contains approximately one helix for every beta strand, variants that form beta-alpha superhelix folds sometimes have long loops rather than helices linking successive beta strands.
One leucine-rich repeat variant domain (LRV) has a novel repetitive
beta-sheets present in other leucine-rich repeats.[6]
Associated domains
Leucine-rich repeats are often flanked by
C5orf36
They also co-occur with LRR adjacent domains. These are small, all
beta sheets that follow the classical connectivity of Ig-domains. The beta strands in one of the sheets is, however, much smaller than in most standard Ig-like domains, making it somewhat of an outlier.[7][8][9]
An
4Fe:4S cluster, and a larger C-terminal domain containing the LRV repeats.[6]Biochemical studies revealed that the 4Fe:4S cluster is sensitive to oxygen, but does not appear to have reversible redox
