Teschmit Nicole, Horke Daniel A, Küpper Jochen
Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607, Hamburg, Germany.
The Hamburg Center for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761, Hamburg, Germany.
Angew Chem Int Ed Engl. 2018 Oct 15;57(42):13775-13779. doi: 10.1002/anie.201807646. Epub 2018 Sep 24.
Atomic-resolution-imaging approaches for single molecules, such as coherent X-ray diffraction at free-electron lasers, require the delivery of high-density beams of identical molecules. However, even very cold beams of biomolecules typically have multiple conformational states populated. We demonstrate the production of very cold (T ≈2.3 K) molecular beams of intact dipeptide molecules, which were then spatially separated into the individual populated conformational states. This is achieved using the combination of supersonic expansion laser-desorption vaporization with electrostatic deflection in strong inhomogeneous fields. This represents the first demonstration of a conformer-separated and rotationally cold molecular beam of a peptide, which enables the investigation of conformer-specific chemistry using inherently non-conformer-specific techniques. It furthermore represents a milestone toward the direct structural imaging of individual biological molecules with atomic resolution by ultrafast diffractive-imaging methods.
用于单分子的原子分辨率成像方法，如自由电子激光的相干X射线衍射，需要输送高密度的相同分子束。然而，即使是非常冷的生物分子束通常也存在多种构象状态。我们展示了完整二肽分子的极冷（T≈2.3K）分子束的产生，然后将其在空间上分离为各个占据的构象状态。这是通过在强非均匀场中结合超声速膨胀激光解吸汽化与静电偏转来实现的。这代表了肽的构象异构体分离且旋转冷分子束的首次展示，它能够使用本质上非构象异构体特异性的技术来研究构象异构体特异性化学。此外，这代表了通过超快衍射成像方法对单个生物分子进行原子分辨率直接结构成像的一个里程碑。
