Table II.

Key residues of cdk2 in the cdk2/cyclin interface are identified by PP_SITE

	1FIN (CDK2/Cyclin A)		1W98 (CDK2/Cyclin E1)	2JGZ (CDK2/Cyclin B1)	1E9H (CDK2/Cyclin A3)		2CCH (CDK2/Cyclin A2)
	A/B	C/D	A/B	A/B	A/B	C/D	A/B	C/D
L37			+	+	+	+
E40	++	++			++	++
T41				+
E42			++	++	++	++	++	++
V44	++	++	++	++	++	++	++	++
I49	++	++	++	++	++	++	++	++
R50	+	+	++	++	++	++	++	++
I52	+	++	++	+	++	++	++	++
S53				+
K56	+	+	+		+		+	+
E57	+	+	++	+	+	+	+	+
V69	+	++	+	+	+	+	+	+
H71	++	+	+	++	++	+	++	++
E73			+	+	+	+
L76		+	++	++	+			+
S120								+
H121				+
R122	+	+	++	+	+	+	+	+
R150	+	+	++	+	++	++	+	++
F152	++	++	++	++	++	++	++	+
V154	++	++	++	++	++	++	++	++
P155	+	+	++	+	++	++	++	++
V156			++				++
R157	+	++	+	+	+	+	+	+
Y159	++	++
E162		+	+		+	+	+	+
K178			+
Y179	+		++				+
N272	+			+
K278	++	+	+	+	+	+	+	++

Symbols of + and ++ denote the important residues in an increasing order of their contribution to the interaction energy of the interface. Residues shown in bold are significantly involved across all cdk2/cyclin interfaces that were analyzed using the structure of the cdk2/cyclin complex reported in PDB files: 1FIN, 1W98, 2JGZ, 1E9H, and 2CCH. Here A/B (C/D) indicates that the interface chosen for analysis is between chain A and chain B (chain C and chain D) in the corresponding PDB file.