Mapelli C, Elrod L F, Switzer F L, Stammer C H, Holt E M
Biopolymers. 1989 Jan;28(1):123-8. doi: 10.1002/bip.360280114.
The effects of replacing L-pyroglutamic acid with the cyclopropane analogue 2,3-methanopyroglutamic acid (2,3-MeGlp) on conformation and enzymatic stability have been investigated in 2,3-MeGlp-NHMe and the novel thyrotropin releasing hormone (TRH) analogue [2,3-MeGlp1]-TRH by x-ray diffraction and nmr. While 2,3-MeGlp-NHMe adopts a folded conformation (small psi angle) in the solid state, several conformations are available to the molecule in solution. 1H-nmr of the diastereomeric mixture [(+/- )-2,3-MeGlp1]-TRH indicates a close orientation of the pyrrolidone and imidazole rings. The 2,3-MeGlp-His amide bond is considerably more stable to pyroglutamate aminopeptidase than the Glp-His bond in TRH.
通过X射线衍射和核磁共振研究了用环丙烷类似物2,3-亚甲基焦谷氨酸（2,3-MeGlp）取代L-焦谷氨酸对2,3-MeGlp-NHMe和新型促甲状腺激素释放激素（TRH）类似物[2,3-MeGlp1]-TRH的构象和酶稳定性的影响。虽然2,3-MeGlp-NHMe在固态中采用折叠构象（小ψ角），但该分子在溶液中有几种构象。非对映体混合物[(+/-)-2,3-MeGlp1]-TRH的1H-核磁共振表明吡咯烷酮环和咪唑环的取向紧密。与TRH中的Glp-His键相比，2,3-MeGlp-His酰胺键对焦谷氨酸氨基肽酶的稳定性要高得多。
