Makwana Kamlesh Madhusudan, Mahalakshmi Radhakrishnan
Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal-462023, India.
Phys Chem Chem Phys. 2015 Feb 14;17(6):4220-30. doi: 10.1039/c4cp04991h.
The specific contribution of the acidic-aromatic β-sheet favouring amino acid tyrosine to the stability of short octapeptide β-hairpin structures is presented here. Solution NMR analysis in near-apolar environments suggests the energetically favourable mode of interaction to be T-shaped face-to-edge (FtE) and that a Trp-Tyr interacting pair is the most stabilizing. Alternate aryl geometries also exist in solution, which readily equilibrate between a preferred π···π conformation to an aromatic-amide conformation, without any change in the backbone structure. While the phenolic ring is readily accommodated at the "edge" of FtE aryl interactions, it exhibits an overall lowered contribution to scaffold stability in the "face" orientation. Such differential tyrosine interactions are key to its dual nature in proteins.
本文介绍了有利于酸性芳香族β-折叠的氨基酸酪氨酸对短八肽β-发夹结构稳定性的具体贡献。在近非极性环境中的溶液核磁共振分析表明，能量上有利的相互作用模式是T形面对面（FtE），并且Trp-Tyr相互作用对是最稳定的。溶液中也存在交替的芳基几何结构，它们很容易在优选的π···π构象和芳香酰胺构象之间平衡，而主链结构没有任何变化。虽然酚环很容易容纳在FtE芳基相互作用的“边缘”，但它在“面”方向上对支架稳定性的总体贡献较低。这种不同的酪氨酸相互作用是其在蛋白质中双重性质的关键。
