Antiparallel ?-Sheet Conformation in Cyclopeptides Containing a Pseudo-amino Acid with a biphenyl moiety
作者:Volker Brandmeier、Wolfgang H. B. Sauer、Martin Feigel
DOI:10.1002/hlca.19940770110
日期:1994.2.9
The biphenyl-containing pseudo-amino acids 2′-(aminomethyl)biphenyl-2-carboxylic acid (Abc; 1) and 2′-(aminomethyl)biphenyl-2-acetic acid (Aba; 2) are used as rigid spacers in the backbone of the cyclic peptides cyclo (-Abc-Ala-Phe-Gly-)2 (5), cyclo(-Abc-Ala-Val-Gly-)2 (6), cyclo(-Aba-Gly-Phe-Ala-)2 (7), and cyclo(-Aba-Ala-Phe-Gly-)2(8). Three different interconverting diastereoisomers are found in
含联苯的假氨基酸2'-(氨基甲基)联苯-2-羧酸(Abc; 1)和2'-(氨基甲基)联苯-2-乙酸(Aba; 2)被用作硬性间隔基环状肽的骨架环(-Abc-Ala-Phe-Gly-)2(5),环(-Abc-Ala-Val-Gly-)2(6),环(-Aba-Gly-Phe-Ala- )2(7)和环(-Aba-Ala-Phe-Gly-)2(8)。由于联苯单元的阻转异构性,在每种环肽的溶液中发现了三种不同的互变非对映异构体。NMR技术和分子动力学计算可以得出结论,(D 6)DMSO中5(和6)的主要非对映异构体采用β-折叠构象。本发明提出,伪氨基酸1的(- [R)-chirality形式,具有连接的L-氨基酸,相当于β转角的H结合图案(参见d在图4和˚F)。