Theoretical Study On The Interactions Between NCp7Zinc Finger Domains In HIV-1Virus And Ligand

We studied zinc finger protein and ligands by using quantum chemistry method andatom–bond electronegativity equalization method (ABEEMσπ).1. The structures of the four zinc finger proteins and the thirty one ligands wereoptimized at B3LYP/6-311++G(d,p) level. HF/STO-3G level is used to calculate theirMulliken charge distribution. Then the parameters of ABEEMσπ model (including thereference charge, valence-state electronegativity, valence-state hardness) are determined byusing linear regression and least squares. Hereafter, the charge distributions of the four zincfinger proteins and eleven ligands are obtained by using the ABEEMσπ parameters. The slopek of the linear correlation equation of the charge distribution of ABEEMσπ method and abinitio is close to1.0000, the intercept b is close to0.0000, the linear correlation coefficient Ris over0.9434. So, the results which calculated by ABEEMσπ method are in accordance withthose by ab initio method. It can be demonstrated that the ABEEMσπ parameters are suitableand transferable and can be employed to calculate the charge distributions of the similarsystems.2. ABEEMσπ method was employed to calculate the dipole moments of four zinc fingerproteins and31ligands molecules. The dipole moments calculated by ABEEMσπ method arein agreement with those form. This shows that the ABEEMσπ (valence-state electronegativity,valence-state hardness) parameters are suitable.3. The activity sites of four zinc finger protein are predictd by generalized Fukui function.The largerest of generalized Fukui functions are S16，S16，S69，S72of cysteine in four zincfinger protein, respectively. We calculated the square sum of differences of generalized localsoftness between S atoms in four zinc finger proteins and interaction center atoms of ligands.Softness-matching criterion in local HSAB principle was used to predict the strength ofinteractions between zinc finger proteins and ligands.4. The calibrated ABEEMσπ paramenters (including valence-state electronegativity andvalence-state hardness) were used to calculate the charge distributions of33zinc fingerproteins. Our results are good correlations with the results obtained from ab initioHF/STO-3G. It demonstrates the ABEEMσπ paramenters are transferable and suitable.