猪心肌高铁肌红蛋白高级结构动态信息的光谱指认

Spectral Assignment of Dynamic Structure Information of Porcine Myocardial Metmyoglobin (pMetMb)

本实验采用扫描电子显微镜、X射线衍射、拉曼、红外等现代光谱技术和数据库、计算软件等,层层剖析猪心肌高铁肌红蛋白(pig metmyoglobin,p Met Mb)冻干粉的结构特征和分子动态结构信息。结果表明,p Met Mb冻干粉表观呈明显的棱状结晶体,结晶度为(95.60±1.37)%,三晶胞轴长不相等(a≠b≠c),可归属于高晶度含水单斜结晶体。根据晶体数据库同类化合物比对,得到p Met Mb肽链和heme-Fe的关键基团来源;经拉曼和红外光谱解析和推算,p Met Mb肽链均有α螺旋、β折叠、β转角和无规卷曲4种蛋白质二级结构,分别占50%、14%、24%和12%;分别由3个酰胺区中C=O、C=C、C—N、—COO-、C—H、N—H的不同振动形式所产生;六配位低自旋的Fe—C—N形成heme-Fe3+。因此,p Met Mb为六配位低自旋构象,是结构紧密、性质稳定的球状蛋白质。

The dynamic molecular structures and domains of porcine myocardial metmyoglobin（p Met Mb） were studied and analyzed by scanning electron microscopy, X-ray diffraction, Raman and Infrared spectroscopy with matched databases and softwares. Obviously prismatic crystalline structures were observed on the surface of lyophilized p Met Mb powder. The crystallinity of p Met Mb was（95.60 ± 1.37）%, and it was highly crystalline and monoclinic powder because the lengths of its three-dimensional unit cell were inequality（a ≠ b ≠ c）. By comparison with crystal databases the source of heme-Fe domain in p Met Mb was identified. The Raman and Infrared spectra proved that the peptide chain of p Met Mb contained 50% α-helix, 14% β-fold, 24% β-turn and 12% random coil, which came from the different shake forms C=O, C=C, C-N,-COO-, C-H and N-H in the amide I, II and III regions. The heme-Fe domain in p Met Mb formed by imidazole group（C3H4N2） binding with Fe3＋. So it belonged to globin with compact structure and stable properties.