A capping domain for LRR protein interaction modules

Leucine-rich repeats (LRR) are protein interaction modules which are presen t in a large number of proteins with diverse functions. Wt describe here a novel motif (16-19 residues) downstream of the last, incomplete, LRR in a s ubfamily of LRR proteins. In the U2A' spliceosomal protein, this motif is f olded into a cap that shields the hydrophobic core of the LRRs from the sol vent. Modelling of the LRR-cap in the imidazoline-1 candidate receptor, usi ng the known structure of U2A' as template, showed a conservation of the ba sic structural features. (C) 1999 Federation of European Biochemical Societ ies.