LRRs

LRRs, or Leucine-Rich Repeats, are short, conserved protein motifs characterized by a repeating sequence rich in leucine residues. These motifs are typically 20–30 amino acids long and form a distinctive structural motif known as the leucine-rich repeat domain. LRRs are widespread across many species, including bacteria, plants, and animals, where they play crucial roles in protein-protein interactions, immune response, and cellular signaling.

The structure of LRRs consists of an α-helix and β-sheet arrangement that creates a horseshoe-shaped or solenoid architecture. This configuration provides a versatile platform for molecular recognition, allowing LRR-containing proteins to bind specifically to diverse ligands, pathogens, or other cellular molecules.

In biological systems, LRRs are integral components of various receptor proteins, such as Toll-like receptors (TLRs) in the immune system, which detect pathogenic molecules and initiate immune responses. They are also found in proteins involved in cell adhesion, development, and signaling pathways.

The functional versatility of LRRs is attributed to their modular nature, enabling the evolution of complex receptor and signaling proteins. Mutations or alterations in LRR regions can impact their ligand-binding capabilities, affecting immune functions or developmental processes.

Research on LRRs continues to reveal insights into their structural diversity and mechanisms of action, highlighting their potential as targets for therapeutic intervention in immune-related diseases and cancer. Overall, LRRs are a fundamental structural motif that underpins numerous biological processes across different organisms.