Guthold M, Bezanilla M, Erie D A, Jenkins B, Hansma H G, Bustamante C
Institute of Molecular Biology, University of Oregon, Eugene 97403.
Proc Natl Acad Sci U S A. 1994 Dec 20;91(26):12927-31. doi: 10.1073/pnas.91.26.12927.
The capability of the scanning force microscope (SFM) to image molecules in aqueous buffers has opened the exciting possibility of following processes of molecular assembly in real time and in near-physiological environments. This capability is demonstrated in this paper by following the assembly process of RNA polymerase-DNA complexes. DNA fragments deposited on mica and imaged in Hepes/MgCl2 are shown before and after Escherichia coli RNA polymerase holoenzyme is injected in the SFM liquid chamber. The protein can recognize and bind to these DNA fragments within several seconds after injection, suggesting that the protein and the DNA retain their native configuration after deposition and during SFM imaging. A time-lapse sequence depicting the process of assembly of RNA polymerase-DNA complexes is shown. These results represent the first step for acquiring the capabilities to monitor complex biomolecular processes as they take place in ionic solutions and to characterize their spatial organization.
扫描力显微镜（SFM）在水性缓冲液中对分子成像的能力开启了在近生理环境中实时跟踪分子组装过程的令人兴奋的可能性。本文通过跟踪RNA聚合酶-DNA复合物的组装过程来证明这种能力。在将大肠杆菌RNA聚合酶全酶注入SFM液室之前和之后，展示了沉积在云母上并在Hepes/MgCl2中成像的DNA片段。注入后几秒钟内，蛋白质就能识别并结合这些DNA片段，这表明蛋白质和DNA在沉积后以及SFM成像过程中保持了它们的天然构象。展示了一个描绘RNA聚合酶-DNA复合物组装过程的延时序列。这些结果代表了获得监测离子溶液中复杂生物分子过程及其空间组织特征能力的第一步。
