George C, Flippen-Anderson J L, Bianco A, Crisma M, Formaggio F, Toniolo C
Naval Research Laboratory, Washington, DC, USA.
Pept Res. 1996 Nov-Dec;9(6):315-21.
The molecular and crystal structures of four peptides containing one L-Trp guest residue in Aib (alpha-aminoisobutyric acid or C alpha-methyl alanine) host oligopeptide chains have been determined by X-ray diffraction. The peptides are Z-Aib-L-Trp-Aib-OMe, Z-(Aib)2-L-Trp-Aib-OMe, Z-(Aib)3-L-Trp-Aib-OtBu and Boc-(Aib)3-L-Trp-Aib-OMe. Right-handed beta-turns and incipient and fully developed 3(10)-helices are formed in the crystal state by the tri-, tetra- and pentapeptides, respectively. The Trp residue is easily accommodated in these folded structures. The average geometry and preferred conformation for the Trp indolyl side chain are also discussed.
通过X射线衍射确定了在Aib（α-氨基异丁酸或α-甲基丙氨酸）主体寡肽链中含有一个L-Trp客体残基的四种肽的分子结构和晶体结构。这些肽分别是Z-Aib-L-Trp-Aib-OMe、Z-(Aib)2-L-Trp-Aib-OMe、Z-(Aib)3-L-Trp-Aib-OtBu和Boc-(Aib)3-L-Trp-Aib-OMe。三肽、四肽和五肽在晶体状态下分别形成右手β-转角以及初始和完全形成的3(10)-螺旋。Trp残基很容易容纳在这些折叠结构中。还讨论了Trp吲哚基侧链的平均几何结构和优选构象。
