Singh S, Gupta J, Kharbanda R, Sharma R
Division of Biopolymers, Central Drug Research Institute, Lucknow.
Indian J Biochem Biophys. 1992 Feb;29(1):65-9.
A comparison between conformations of native and methylamine modified human plasma low density lipoproteins (hydrated density 1.032-1.043 g/ml) has been presented. Near UV circular dichroism and difference absorption spectra of modified low density lipoprotein have suggested substantial differences in the local environments of several aromatic amino acid side chains. Relatively lower ellipticity at 222 nm of modified lipoprotein indicated alterations in the secondary structures of its protein moiety. Nucleophilic reaction of methylamine did not cause the peptide bond scission but it brought conformational transition such that some of the buried hydrophobic domains of the protein moiety got exposed to the aqueous environment.
本文对天然和甲胺修饰的人血浆低密度脂蛋白（水合密度1.032 - 1.043 g/ml）的构象进行了比较。修饰后低密度脂蛋白的近紫外圆二色光谱和差示吸收光谱表明，几个芳香族氨基酸侧链的局部环境存在显著差异。修饰后脂蛋白在222 nm处的椭圆率相对较低，表明其蛋白质部分的二级结构发生了改变。甲胺的亲核反应并未导致肽键断裂，但引发了构象转变，使得蛋白质部分一些埋藏的疏水结构域暴露于水环境中。
