Mayes Maricris L, Perreault Lisa
Department of Chemistry and Biochemistry, University of Massachusetts Dartmouth, North Dartmouth, Massachusetts 02747, United States.
ACS Omega. 2019 Jan 10;4(1):911-919. doi: 10.1021/acsomega.8b02934. eCollection 2019 Jan 31.
Tyrosine-based dipeptides self-assemble to form higher order structures. To gain insights into the nature of intermolecular interactions contributing to the early stages of the self-assembly of aromatic dipeptides, we study the dimers of linear dityrosine (YY) and tryptophan-tyrosine (WY) using quantum-chemical methods with dispersion corrections and universal solvation model based on density in combination with energy decomposition and natural bond orbital (NBO) analyses. We find that hydrogen bonding is a dominant stabilizing force. The lowest energy structure for the linear YY dimer is characterized by O···H(O). In contrast, the lowest energy dimer of linear WY is stabilized by O···H(N) and π···π. The solvent plays a critical role as it can change the strength and nature of interactions. The lowest energy for linear WY dimer in acetone is stabilized by O···H(O), π···H(C), and π···H(N). The Δ of dimerization and stabilization energies of solvated dipeptides reveal that the dipeptide systems are more stable in the solvent phase than in gas phase. NBO confirms increased magnitudes for donor-acceptor interaction for the solvated dipeptides.
基于酪氨酸的二肽会自组装形成更高阶的结构。为深入了解有助于芳香族二肽自组装早期阶段的分子间相互作用的本质，我们使用带有色散校正的量子化学方法以及基于密度的通用溶剂化模型，并结合能量分解和自然键轨道（NBO）分析，研究了线性二酪氨酸（YY）和色氨酸 - 酪氨酸（WY）的二聚体。我们发现氢键是主要的稳定作用力。线性YY二聚体的最低能量结构以O···H(O)为特征。相比之下，线性WY的最低能量二聚体则通过O···H(N)和π···π得以稳定。溶剂起着关键作用，因为它可以改变相互作用的强度和性质。线性WY二聚体在丙酮中的最低能量通过O···H(O)、π···H(C)和π···H(N)得以稳定。溶剂化二肽的二聚化和稳定化能量的Δ表明，二肽体系在溶剂相中比在气相中更稳定。NBO证实溶剂化二肽的供体 - 受体相互作用强度有所增加。
