Table 1. EGFR CT domain P-site sequences.

P-site	Sequence*	Category**	kcat/KM***	vphos****
992	DADEYLIPQ	Minor	74.9	8.4
1045	FLQRYSSDP	Minor	-	-
1068	PVPEYINQS	Major	65.4	3.3
1086	QNPVYHNQP	Major	12.1	0.3
1101	RDPHYQDPH	-	-	-
1114	GNPEYLNTV	Minor	49.8	1.7
1148	DNPDYQQDF	Major	71.2	2.8
1173	ENAEYLRVA	Major	64.0	2.9

The sequences surrounding each of the eight tyrosine residues in the EGFR CT domain are shown, with the tyrosine identifying the P-site highlighted in bold.

Qualitative categorization based on the consensus of experiments characterizing major or minor sites of EGFR self-phosphorylation (see Table 2; -, phosphorylation not detected).

Steady state catalytic efficiencies k_cat/K_M (in units of mM⁻¹ min⁻¹) characterizing the phosphorylation of synthetic peptide substrates containing the P-site sequences by the ligand-activated EGFR as determined by Fan et al. [8] (-, not determined).

Predicted relative initial velocities of P-site self-phosphorylation computed as v_phos = k′_intra.(k_cat/K_M), where k′_intra is relative frequency of binding site interactions for each P-site (the sums for those in both receiver and activator molecules) in simulations performed in the absence of CT domain electrostatic interactions (see Fig. 9 and Supporting Information, Text S1).