【摘 要】
：
A computational study by combining molecular dynamics simulations with density functional theory calculations has been conducted on two unnatural octapeptides,Boc-[Aib-β3(R)Val]4-OMe and Boc-[Aib-α(S)
【机 构】
：
School of Chemistry and Chemical Engineering,Key Laboratory of Mesoscopic Chemistry of MOE,Institute
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A computational study by combining molecular dynamics simulations with density functional theory calculations has been conducted on two unnatural octapeptides,Boc-[Aib-β3(R)Val]4-OMe and Boc-[Aib-α(S)Val]4-OMe[1],and the corresponding infinite one-dimensional chains to understand their inherent structural preferences and the effect of the crystal environment on their structures.[2] For both systems,we have determined their gas-phase lowest-energy conformers,which possess hybrid helical structures(not pure α-helix-like or 310-helix-like).For Boc-[Aib-β3(R)Val]4-OMe,our calculations show that the corresponding infinite polypeptide has an α-helix-like structure as the most stable structure.This result is in accord with the experimental crystal structure.For Boc-[Aib-α(S)Val]4-OMe,our calculations show that the infinite polypeptide will exist in 310-helix-like structure,which is also consistent with the observed crystal structure.The present study demonstrates that the peptide conformer in the crystal environment does not necessarily correspond to the most stable structure in vacuum.
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