Groups 1 and 2 have a serine-rich region and an " arginine element " ( RRLPIF ) at the carboxyl terminus .
groups 1 and 2 have a serine-rich region and an " arginine element " ( rrlpif ) at the carboxyl terminus .
O O O O O O B-protein_domain_or_region I-protein_domain_or_region O O O B-protein_substructure I-protein_substructure O O B-protein_domain_or_region O O O B-protein_domain_or_region I-protein_domain_or_region O