3D-QSAR and Docking Studies of a Series of β-Carboline Derivatives as Antitumor Agents of PLK1

Table 3

The variables with the highest impact (positive or negative) in the final GRIND model and the structural elements of the most active (57 and 58) and inactive (3 and 45) compounds associated with these variables.

Node pair	GRIND		Interpretation
	Variable no.; (Å)	Impact (coefficient)
TIP-TIP	42, 43; (16.8–17.2)	Inverse; (−0.23, −0.24)	Shape of ring A and one of the methoxy substituents in 3,4,5-trimethoxyphenyl at position 1 for 3 and shape of pentafluorobenzoxyl at position 7 and hydrogens of ring C for 45
TIP-TIP	52; (20.8)	Direct; (0.21)	Shape of pentafluorobenzoxyl at position 7 and N^2-arylated substituent for 57 and shape of 7-n-butoxy and 2-benzyl for 58
DRY-DRY	24; (9.6)	Direct; (0.2)	Hydrophobic properties of ring A and phenyl ring in 2-benzyl substituent for 57 and 58
N1-N1	8; (3.2)	Inverse; (−0.18)	Interaction of carboxyl at position 3 with the probe N1 for 3 and interaction of oxygen atom in pentafluorobenzoxyl group at position 7 with probe N1 for 45
TIP-TIP	44; (17.6)	Inverse; (−0.18)	Shape of ring A and one of the methoxy substituents in 3,4,5-trimethoxyphenyl at position 1 for 3 and shape of pentafluorobenzoxyl at position 7 and hydrogens of ring C for 45
N1-TIP	10; (4)	Inverse; (−0.18)	Shape of 3-carboxyl and the interaction of ring C with probe N1 for 3 and interaction of hydrogens of ring A with probe N1 and the shape of ethyl substituent in ring B (TIP) for 45
DRY-DRY	25; (10)	Direct; (0.17)	Hydrophobic properties of ring A and phenyl ring in 2-benzyl substituent for 57 and hydrophobic properties of ring B and 2-benzyl for 58
N1-TIP	24; (9.6)	Direct; (0.15)	Shape of 2-benzyl ring (TIP) and nitrogen of ring C (N1) for 57 and shape of i-butyl substituent in ring B and interaction of nitrogen in ring C with probe N1 for 58
N1-TIP	7; (2.8)	Inverse; (−0.15)	Shape of 3-carboxyl and the interaction of ring C with probe N1 for 3. This variable is absent from compound 45
TIP-TIP	56; (22.4)	Direct; (0.13)	Shape of pentafluorobenzoxyl at position 7 and N^2-arylated substituent for 57. This variable is absent from compound 58
N1-TIP	23; (9.2)	Direct; (0.13)	Shape of N^2-benzyl and the interaction of oxygen in pentafluorobenzoxyl group with probe N1 for 57 and shape of 7-n-butoxy and the interaction of N in ring C with the probe N1 for 58
N1-N1	28; (11.2)	Direct; (0.1)	Interaction of nitrogen in ring C and O in pentafluorobenzoxyl group with probe N1 for 57 and interaction of nitrogen in ring C and O in 7-n-butoxy group with probe N1 for 58