Design and synthesis of trans-3-aminopyran-2-carboxylic acid (APyC) and α/β-peptides with 9/11-helix
作者:Gangavaram V. M. Sharma、Kodeti Srinivas Reddy、Shaik Jeelani Basha、Kondreddi Ravinder Reddy、Akella V. S. Sarma
DOI:10.1039/c1ob06279d
日期:——
A new β-amino acid, trans-3-aminopyran-2-carboxylic acid (APyC), was designed and synthesized from (R)-glyceraldehyde derivative and used in the synthesis of α/β-peptides in a 1â:â1 alternating pattern with D-Ala. The presence of oxygen atom at the Cβ2-position in APyC was envisaged to provide opportunity for additional interaction. These hybrid peptides have shown the presence of 9/11-helix through extensive NMR and MD studies. The amide protons of D-Ala, in addition to participating in 9-mr H-bonding with CO of succeeding β-residue, were also involved in additional electrostatic interaction with pyran ring oxygen of preceding β-residue, which facilitated further stabilization to the 9/11-mixed helix. The study thus results in a new âmotifâ for a 9/11-helix, and the first example from a cyclic β-amino acid.
一种新的β-氨基酸,反式-3-氨基吡喃-2-羧酸(APyC),是从(R)-甘油醛衍生物设计和合成的,并用于与D-丙氨酸以1:1交替模式合成α/β-肽。APyC在Cβ2位置的氧原子的存在被设想可以提供额外的相互作用机会。通过广泛的核磁共振和分子动力学研究表明,这些杂化肽显示出9/11-螺旋结构的存在。D-丙氨酸的酰胺质子除了与后续β-残基的CO参与9元环氢键外,还与前面β-残基的吡喃环氧原子发生额外的静电相互作用,这进一步稳定了9/11-混合螺旋。该研究因此得到了一个新的9/11-螺旋"��序",这是首个来自环状β-氨基酸的例子。