摘要
A fluctuating charge interaction potential function for alanine-water was constructed in the spirit of newly developed ABEEMax/MM（atom-bond electronegativity equalization method at the azc level fused into molecular mechanics）. The properties of gaseous neutral alanine-（H20）n（n=l--7） clusters were systematically investigated by quantum mechanics（QM） and the constructed ABEEMax/MM potential, such as conformations, hydrogen bonds （H-bonds）, interaction energies, charge distributions, and so on. The results of ABEEM^rrc/MM model are in fair agreement with those of QM and available experimental data. For isolated alanine, compared with those of experi- mental structure, the average absolute deviations（AAD） of bond length and bond angle are 0.002 nm and 1.4~, re- spectively. For alanine-water clusters, the AAD of interaction energies and H-bond lengths are only 3.77 kJ/mol and 0.012 nm, respectively, compared to the results of MP2/aug-cc-pVDZ//MP2/6-31 I＋G＊＊ method. The ABEEMa charges fluctuate with the changing conformation of the system, and can accurately and reasonably reflect the inter- polarization between water and alanine. The presented alanine-water potential function may provide a basis for fur- ther simulations on related aqueous solutions ofbiomolecules.
A fluctuating charge interaction potential function for alanine-water was constructed in the spirit of newly developed ABEEMax/MM（atom-bond electronegativity equalization method at the azc level fused into molecular mechanics）. The properties of gaseous neutral alanine-（H20）n（n=l--7） clusters were systematically investigated by quantum mechanics（QM） and the constructed ABEEMax/MM potential, such as conformations, hydrogen bonds （H-bonds）, interaction energies, charge distributions, and so on. The results of ABEEM^rrc/MM model are in fair agreement with those of QM and available experimental data. For isolated alanine, compared with those of experi- mental structure, the average absolute deviations（AAD） of bond length and bond angle are 0.002 nm and 1.4~, re- spectively. For alanine-water clusters, the AAD of interaction energies and H-bond lengths are only 3.77 kJ/mol and 0.012 nm, respectively, compared to the results of MP2/aug-cc-pVDZ//MP2/6-31 I＋G＊＊ method. The ABEEMa charges fluctuate with the changing conformation of the system, and can accurately and reasonably reflect the inter- polarization between water and alanine. The presented alanine-water potential function may provide a basis for fur- ther simulations on related aqueous solutions ofbiomolecules.
基金
Supported by the National Natural Science Foundation of China（Nos.21133005, 20703022 and 21011120087） and the Project of Educational Bureau of Liaoning Province, China（No.2009T057）.
