杜仲抗真菌蛋白(EAFP)晶体动态生长研究

EAFP crystal growth observed by in situ atomic force microscopy

杜仲抗真菌蛋白(eucommia antifungal protein,EAFP),含有41个氨基酸残基,其中有10个半胱氨酸,半胱氨酸间形成的二硫桥键使分子构象很稳定.EAFP的晶体属单斜晶系,空间群为P21,晶胞参数为:a=1.9085nm,b=2.3225nm,c=3.0854nm10-6,β=98.64,分子量为4158.9.EAFP晶体生长速度快,对X射线的衍射能力强,很值得研究其生长的机理.利用原子力显微镜(AFM)对EAFP晶体的{100}面进行动态的生长研究,发现在中低过饱和度下主要以各向异性的单双链螺旋位错的生长模式进行生长,详细研究了这种螺旋的形成机制,并探讨了其结构基础.

EAFP（eucommia antifungal protein） is a cysteine-rich peptide consisting of 41 amino residues. EAFP crystals belong to monoclinic form, with P21 space group and the unit cell parameters： a=1. 908 5 nm, b=2. 322 5 nm, c=3. 085 4 nm, β=98.64, M. W. =4 158.9. To our surprised, EAFP crystals grow much faster than most of other macromolecular crystals. We have studied the{ 100} faces of the EAFP crystals by in situ a- tomic force microscopy in their mother liquor. One type of different anisotropic singledouble-like spiral dislocation was found on the{100} faces of EAFP crystals. We have also studied the spiral dislocation sources in more details to find its formation process at low-to-moderate supersaturations and discussed its crystallographic basis to control source center and the whole dislocation growth topography.