A Close Look at Proteins: Submolecular Resolution of Two- and Three-Dimensionally Folded Cytochrome c at Surfaces
A Close Look at Proteins: Submolecular Resolution of Two- and Three-Dimensionally Folded Cytochrome c at Surfaces
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DOI：
10.1021/nl3005385
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发表时间：
2012-05-01
期刊：
影响因子：
10.8
通讯作者：
Kern, Klaus
中科院分区：
文献类型：
--
作者：
Deng, Zhitao;Thontasen, Nicha;Kern, Klaus
由于蛋白质与高分辨率扫描探针显微镜所需的真空环境的不相容性，到目前为止，在单个氨基酸水平上对单个蛋白质分子进行成像是不可能的。在这里，我们展示了选择性折叠和未折叠的细胞色素c蛋白质离子的电喷雾离子束沉积在原子定义的固体表面上的超真空（10（-10）毫巴），并实现前所未有的分辨率与扫描隧道显微镜。在表面上，折叠的蛋白质被发现保持其三维结构。未折叠的蛋白质被观察为延伸的聚合物链，显示亚分子特征，在氨基酸水平上具有分辨率。在弱相互作用的表面上，未折叠的蛋白质重新折叠成由单个分子组成的平坦、不规则的斑块。这表明，二维限制折叠的肽的适当的序列成规则的二维结构作为一种新的方法对功能分子表面涂层的可能性。
Imaging of individual protein molecules at the single amino acid level has so far not been possible due to the incompatibility of proteins with the vacuum environment necessary for high-resolution scanning probe microscopy. Here we demonstrate electrospray ion beam deposition of selectively folded and unfolded cytochrome c protein ions on atomically defined solid surfaces in ultrahigh vacuum (10(-10) mbar) and achieve unprecedented resolution with scanning tunneling microscopy. On the surface folded proteins are found to retain their three-dimensional structure. Unfolded proteins are observed as extended polymer strands displaying submolecular features with resolution at the amino acid level. On weakly interacting surfaces, unfolded proteins refold into flat, irregular patches composed of individual molecules. This suggests the possibility of two-dimensionally confined folding of peptides of an appropriate sequence into regular two-dimensional structures as a new approach toward functional molecular surface coatings.