LRR

LRR, or Leucine-Rich Repeat, is a structural motif found in a wide range of proteins across different organisms, including plants, animals, and fungi. Characterized by repetitive sequences rich in leucine residues, LRR motifs typically form a curved, elongated structure that contributes to protein-protein interactions, ligand binding, and signal transduction.

The LRR motif generally consists of 20-29 amino acids with a conserved leucine or other hydrophobic residues at specific positions. These motifs are arranged in tandem repeats, forming a horseshoe-shaped or solenoid structure that facilitates binding interactions with various molecules. The specific sequence and number of repeats can vary, providing versatility in function and target specificity.

Proteins containing LRRs play crucial roles in immune responses, development, and cellular communication. Notable examples include toll-like receptors (TLRs), which recognize pathogen-associated molecular patterns, and some plant resistance proteins involved in pathogen detection. The structural stability and adaptability of LRR domains allow them to mediate diverse biological processes.

Research into LRR structures has provided insights into their mechanisms of action. Crystallography and computational modeling have revealed how variations in tandem repeats alter binding affinity and specificity. Their involvement in disease, notably in autoimmune disorders and cancers, has also made LRR-containing proteins significant subjects of medical research.

Due to their widespread presence and functional importance, LRRs are considered a versatile and evolutionarily conserved structural motif central to biological recognition and signaling processes.