Linear free energy relationships implicate three modes of binding for fluoroaromatic inhibitors to a mutant of carbonic anhydrase II.

[figure: see text] Linear free energy relationships between binding affinity and hydrophobicity for a library of fluoroaromatic inhibitors of F131V carbonic anhydrase II (CA) implicate three modes of interaction. X-ray crystal structures suggest that F131 interacts with fluoroaromatic inhibitors, while P202, on the opposite side of the active site cleft, serves as the site of the hydrophobic contact in the case of the F131V mutant. 2-Fluorinated compounds bind more tightly, perhaps due to the field effect of the nearby fluorine on the acidity of the amide proton.

The pattern of fluorine substitution affects binding affinity in a small library of fluoroaromatic inhibitors for carbonic anhydrase.

[formula: see text] A library of fluoroaromatic inhibitors of carbonic anhydrase has been found to bind in a manner dependent on both hydrophobicity and the pattern of substitution of the fluoroaromatic ring. All of the compounds in the library bind to the protein with Kd < 3 nM. We have inferred two distinct binding modes from our data, which suggest two types of interactions that should be considered when designing fluorinated drugs.

Models of F.H contacts relevant to the binding of fluoroaromatic inhibitors to carbonic anhydrase II.

[formula: see text] Complexes formed between fluorobenzene and N-methylformamide or benzene have been used as models of the interaction of fluoroaromatic drugs with carbonic anhydrase II. These structures have been investigated via ab initio and density functional methods, including HF, B3LYP, and MP2 procedures. The results of the calculations are consistent with the hypothesis, suggested originally by experimental X-ray crystal structures of the drug-receptor complexes, that favorable fluorine-hydrogen interactions affect binding affinity.