Selectively C-deuteriated N-acetylglycine trimer and
tetramer acid types have been synthesized, and their two crystalline
modifications, solid-A and solid-B [which correspond in structure to
polyglycine (PG) II and I, respectively] have been prepared. Raman
scattering spectra have been measured for a series of these glycine
oligomers, and the CH
2
- and CD
2
-characteristic
modes have been investigated in detail. Assignment of the
CH
2
-characteristic bands to each CH
2
group in
the oligomers has been carried out successfully. In particular, the
results obtained from the CD
2
stretch region show that N-
and C-terminal glycine residues for the PGI- and PGII-type trimers and
tetramers are all in very similar environments and that the glycine
residues which are sandwiched between the two terminal residues are
also in a similar environment for both the trimers and the tetramers.
选择性C-重
氘化的
N-乙酰甘氨酸三聚体和四聚体酸类型已被合成,且其两种晶体改型,固体-A和固体-B(分别对应于
聚甘氨酸(
PG)II和I的结构)已被制备。对一系列这些甘
氨酸低聚物进行了拉曼散射谱测量,并详细研究了CH₂和CD₂的特征模式。成功地将CH₂特征带分配给低聚物中的每个CH₂基团。特别是在CD₂伸缩区域获得的结果表明,
PGI型和
PGII型三聚体及四聚体的N-末端和C-末端甘
氨酸残基都处于非常相似的环境中,并且夹在两个末端残基之间的甘
氨酸残基在三聚体和四聚体中也处于相似的环境中。