Contains a central nucleotide-binding (NB) … Contains a central nucleotide-binding (NB) subdomain as part of a larger entity called the NB-ARC domain. C-terminal to the NB-ARC domain lies a leucine-rich repeat (LRR) domain, which is sometimes followed by an extension of variable length. Hence, this group of R proteins is collectively referred to as NB-LRR proteins. If N-terminal region contain a predicted coiled-coil structures (CC), non-TIR NB-LRR proteins are collectively referred to as CC-NB-LRR or CNL. lectively referred to as CC-NB-LRR or CNL.