Carbonic anhydrase inhibitory activity of phthalimide-capped benzene sulphonamide derivatives

Figures & data

Table 1. Inhibition data of CA I and CA II with compounds reported here and the standard sulphonamide inhibitor acetazolamide (ACTZ) by a stopped-flow CO₂ hydrase assay.

Code	R	R1	Ki (nM)^a
			hCA I	hCA II
1	–H	–H	28.5	2.2
2	–CH(CH3)2	–H	>10,000	>10,000
3	–CH2–CH2–C6H5	–H	7352.3	>9641.0
4	–CH3	–CH3	>10,000	9062.9
5	–C2H5	–C2H5	>10,000	>10,000
6	–C6H5	–C6H5	>10,000	>10,000
7	–(CH2)5–		>10,000	>10,000
8	–(CH2)2–N(-CH3)–(CH2)2–		>10,000	>10,000
9	–H	–	>10,000	>10,000
10	2–OH	–	5515.8	8873.4
11	3–OCH3	–	>10,000	>10,000
12	4–OCH3	–	>10,000	>10,000
13	2–Cl	–	>10,000	>10,000
14	3–Cl	–	>10,000	>10,000
15	4–Cl	–	7497.8	>10,000
16	2–CH3	–	>10,000	>10,000
17	3–CH3	–	>10,000	>10,000
18	4–CH3	–	>10,000	>10,000
19	4–C2H5	–	>10,000	>10,000
20	3–NO2	–	>10,000	>10,000
21	4–NO2	–	>10,000	>10,000
22	4–COOH	–	>10,000	>10,000
ACTZ	–	–	250	12

^aMean from three different assays using a stopped-flow technique (errors were in the range of ± 5–10% of the reported values).

Figure 1. A 2D plot illustrating the interaction of ACTZ and compound 1 with human carbonic anhydrase II (PDB: 5E2M). The plot depicts the common interacting residues between the two ligands as red circles, hydrophobic interactions as arcs with red spikes, and H-bonding interactions as dashed green lines. The plot uses colour coding to distinguish between different atoms and bonds, with carbon atoms in black, oxygen atoms in red, nitrogen atoms in blue, sulphur atoms in yellow, and chloro atoms in green. The bonds of the amino acid residues are coloured brown, while the ligands are coloured violet. The zinc ion is presented in pink.

Figure 2. A 2D plot illustrating the interaction of ACTZ and compound 1 with human carbonic anhydrase II (PDB: 5MJN). The plot depicts the common interacting residues between the two ligands as red circles, hydrophobic interactions as arcs with red spikes, and H-bonding interactions as dashed green lines. The plot uses colour coding to distinguish between different atoms and bonds, with carbon atoms in black, oxygen atoms in red, nitrogen atoms in blue, sulphur atoms in yellow, and chloro atoms in green. The bonds of the amino acid residues are coloured brown, while the ligands are coloured violet. The zinc ion is presented in pink.

Figure 3. A 2D plot illustrating the interaction of ACTZ and compound 1 with AF-A0A1S4EX12 (AlphaFold structure). The plot depicts the common interacting residues between the two ligands as red circles, hydrophobic interactions as arcs with red spikes, and H-bonding interactions as dashed green lines. The plot uses colour coding to distinguish between different atoms and bonds, with carbon atoms in black, oxygen atoms in red, nitrogen atoms in blue, sulphur atoms in yellow, and chloro atoms in green. The bonds of the amino acid residues are coloured brown, while the ligands are coloured violet. The zinc ion is presented in pink.

Table 2. Comparative docking data and key residue interactions of ligands ACTZ and compound 1 with human and mosquito carbonic anhydrases.

	Molecule	Docking score (kcal/mol)	Predicted Ki	Interaction types
				Hydrogen bonding	π–π stacking	Hydrophobic
hCA I	ACTZ	−9.43	121.99 nM	Pro201, His94, His96, His119, Thr199		Leu198, Trp209, His200
	1	−10.74	13.34 nM	His94, His96, His119, Thr199, Gln92	Phe91, His94	Phe91, Ala121, Leu131, Leu198, Trp209, Val143, His67,
hCA II	ACTZ	−9.37	135.03 nM	Thr199, His119, His96, His94, Gln92		Trp209, Val143, Leu198, Val121, Phe131,
	1	−11.13	6.9 nM	Thr199, His119, His96, His94, Gln92	Phe131	Phe131, Ile91, Gln92, Val121, Leu198, Val143, Trp209
AF-A0A1S4EX12	ACTZ	−5.74	62.25 µM	His131, Thr213, His114, Thr214, His112	His112	Trp233, Leu212, Val154, Asn79, His81, Thr82,
	1	−7.30	4.47 µM	Thr213, Tyr24, Asn79,	His112	His114, His112, Thr82, His81, Thr214, Val154, Leu152, Trp223, Leu212, Val221

Figure 4. The root mean square deviation plot of AlphaFold (black), hCA I (red), and hCA II (green) with compound 1.

Figure 5. The root mean square fluctuation plot of AlphaFold (black), hCA I (red), and hCA II (green) with compound 1.

Figure 6. The radius of gyration plot of AlphaFold (black), hCA I (red), and hCA II (green) with compound 1.

Figure 7. The solvent-accessible surface area plot of AlphaFold (black), hCA I (red), and hCA II (green) with compound 1.

Figure 8. The RMSD plot of ligand fit to protein backbone of AlphaFold (black), hCA I (red), and hCA II (green) with compound 1.