Table 2. The common and specific coupling pairs from reciprocal coupling analysis.^* .

Common Coupling	Pak2 Residues	Distance	PKA Residues	Distance	Src Residues	Distance	Pair #
	E294-R367	10.1 Å	E91-R165	10.2 Å	E310-R385	9.6 Å	1
	N373-D386	3.6 Å	N171-D184	3.1 Å	N391-D404	2.9 Å	2
	W427-G439	14.8 Å	W222-G234	14.8 Å	W446-G459	15.0 Å	3
	E413-R488	2.6 Å	E208-R280	2.8 Å	E432-R506	2.7 Å	4
Specific Coupling	L481-H497	10.1 Å	L273-H294	10.1 Å			5
	H360-K370	11.8 Å	H158-K168	12.4 Å			6
	G380-P461	25. 3Å	G178-P258	22.5 Å			7
	E324-K383	3.2 Å			E339-K401	2.7 Å	8
	W409-C480	8.8 Å			W428-C498	8.6 Å	9
			Y229-F238	7.4 Å			10

^*The common coupling pairs exist in Pak2, PKA and Src. The specific coupling pairs exist in either one or two protein kinases.

The distance between the two coupling residues is defined as the closest distance in the X-ray crystal structures 1YHV.PDB, 1ATP.PDB and 2SCR.PDB, as measured using the Swiss-Pdb Viewer.