Confromational Studies on Peptides Containing Enantiometric ?-Methyl ?-Amino Acids. Part I. Differential conformational properties of (R)- and (S)-2-methylaspartic acid
作者:Karl-Heinz Altmann、Eva Altmann、Manfred Mutter
DOI:10.1002/hlca.19920750420
日期:1992.6.24
The conformational properties of four model peptides of the general formula Ac-Tyr-Xaa-Yaa-Zaa-Ala-Lys-Glu-ala-Ala-Glu-Lys-Ala-Zaa-Yaa-Xaa-Lys-NH2 (Xaa-Yaa-Zaa = Ala-Ala-(R)-Asp(2-Me), 1; Ala-Ala-(S)-Asp(2-Me), 2; Ala-Aib-Asp, 3; Ala-Ala-Asp, 4; Asp(2-Me) = 2-methylaspartic acid; Aib = 2-aminoisobutyric acid) were studied by CD spectroscopy in solution, to evaluate the helix-inducing potential of enantiomerically
通式为Ac-Tyr-Xaa-Yaa-Zaa-Ala-Lys-Glu-ala-Ala-Glu-Lys-Ala-Zaa-Yaa-Xaa-Lys-NH 2(Xaa- Yaa-Zaa = Ala-Ala-(R)-Asp(2-Me),1 ; Ala-Ala-(S)-Asp(2-Me),2 ; Ala-Aib-Asp,3 ; Ala-Ala-在溶液中通过CD光谱法研究了Asp,4 ; Asp(2-Me)= 2-甲基天冬氨酸; Aib = 2-氨基异丁酸),以评估对映体纯的2-甲基天冬氨酸的螺旋诱导电势作为其对映体的函数C(2)的手性。在中性pH和1°下,所有肽在水溶液中均显示出明显的螺旋形成,螺旋度按顺序增加4 3≈ 1。将pH降低至2会导致肽1的螺旋度显着增加,而非对映异构体肽2现在主要以无序构象存在。通过质子化的(R)-Asp(2-Me)进行的螺旋诱导超过了肽3中Aib诱导的螺旋形成,pH 2下水