(1)H, (13)C and (15)N assignments of EGF domains 4 to 7 of human Notch-1.

The Notch pathway is a core cell-cell signaling system in Metazoa which plays a key role in development and adult homeostasis. Whereas most Notch structural biology research has focused on the negative regulatory region and the intracellular domain, relatively little structural information is available for the extracellular part of human Notch-1 (hN-1) which mediates ligand recognition. This region consists of 36 epidermal growth factor-like (EGF) domains, many of which contain a calcium-binding consensus sequence. The calcium-binding site in each case is located within the N-terminal portion of the domain, and is associated with both intra- and inter-domain rigidity. The absence of calcium-binding sites in EGF6, EGF10 and EGF22, however, suggests that these domains might represent regions of flexibility in the receptor which could influence the cell-surface architecture (usually depicted as an extended rod projecting from the cell surface). To probe this, we have purified a quadruple-domain construct from hN-1, in which the non-calcium-binding EGF6 is flanked by EGF4-5 and EGF7. Here, we report (1)H, (13)C and (15)N resonance assignments for this four-domain 157 amino acid construct. The assignments presented here are the prerequisite for a detailed study of the structure and dynamics of this region of the Notch receptor.