LRR Domain

Domain Binding and Function

Domain binding and function: Leucine-Rich Repeats (LRR) are 22–28 amino acid motifs that are found in a number of proteins with diverse functions and cellular locations. These repeats are usually involved in protein—protein interactions, and in series they form nonglobular, crescent-shaped structures. The crescent shape adopted by series of leucine-rich repeats creates a solventexposed elongated concave surface of parallel β-strands that acts as a scaffold for protein—protein interactions. The particular function of each LRR crescent is specified by different residues arranged in an appropriate orientation on the surface of the structurally conserved three-dimensional fold. For example, RNAse inhibitor and U2A' LRR scaffolds appear to interact with their targets via the concave inner surface of the crescent, while in the case of S. pombe Rna1p, the Ran binding site appears to be located on the side face of the crescent within the loop regions connecting the β-strands and α-helices.

Structure Reference

1. Hillig, R.C. et al. (1999) Mol. Cell 3(6), 781–791.

Examples of Domain Proteins

Binding Examples

FHA Domain Proteins	Binding Partners
RNAse Inhibitor	RNAse
Rna1p	RAN small GTPase
TAP	Constitutive transport element (CTE) of retroviral RNAs
U2A'	Ribonucleoprotein domain of U2B'
CIITA	MHC class II promoter binding complex