Theoretical studies on complexes of calcium ion with amino acids
Penghua Qin , Wencai Lü , Wei Qin , Wei Zhang , Hui Xie
Chemical Research in Chinese Universities ›› 2014, Vol. 30 ›› Issue (1) : 125 -129.
The complexes formed by calcium ion and 12 common amino acids were investigated systematically in the gas phase at the level of MP2/6-311++G(d,p)//MP2/6-31G(d,p). The results show that the salt-bridge structure is the most preferred motif for Ca2+ binding aliphatic amino acids without heteroatom in the side chain, while charge-solvated(CS) structure is the most preferred motif for Ca2+ binding other amino acids except for glutamine and lysine. IR spectra of Gln-Ca2+ and Asn-Ca2+ complexes were calculated and compared well with the available experiments. From the study in aqueous solution, the bidentate salt-bridge structure was determined to be the most favorable for all the twenty kinds of amino acids to chelate Ca2+ to both the oxygen atoms of the negatively carboxylate group in the backbone.
Amino acid / Calcium ion complex / MP2 calculation
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