SEQUENCING OF DNA BY LASER IONIZATION

我们建议开发一种快速测序单链DNA的方法 低聚物和多肽通过反射飞行时间质谱仪， 使用激光解吸、激光电离和激光控制 碎片化。解吸已经存放在 冰冻溶液或固体基质将用脉冲红外进行研究 (IR)和紫外线(UV)激光解吸。被解吸的分子是 带电的中性物质会被真空紫外线电离到表面上方 (真空紫外光)激光束，导致单光子电离；替代方案 要比较的办法是使用紫外光激光，产生 多光子电离。用额外的激光进行可变破碎 光束将作为该激光器波长、功率的函数进行研究 密度和时间关系对电离激光的影响最大 在获得简单可靠的碎片模式方面的控制 序列分配。脱附激光参数对脱附过程的影响 还将检查碎片化。实验旨在 尽可能地将解吸、电离、 和碎片化，以最大限度地控制这些过程。这项技术 每台机器每天可以测序10(6)个核苷酸。

We propose to develop a rapid method for sequencing single-stranded DNA oligomers and polypeptides by reflecting time-of-flight mass spectrometry, using laser desorption, laser ionization, and laser controlled fragmentation. The desorption of DNA segments that have been deposited in a frozen solution or on a solid substrate will be studied by pulsed infrared (IR) and ultraviolet (UV) laser desorption. Desorbed molecules that are neutral in charge will be ionized above the surface by a vacuum ultraviolet (VUV) laser beam, resulting in single-photon ionization; an alternative approach to be compared will be the use of UV laser light, resulting in multiple-photon ionization. Variable fragmentation with an additional laser beam will be investigated as a function of this laser's wavelength, power density, and temporal relationship to the ionizing laser for greatest control in obtaining simple and reliable fragmentation patterns for sequence assignment. The influence of the desorption laser parameters on fragmentation also will be examined.The experiments are designed to decouple as much as possible the three processes of desorption, ionization, and fragmentation for maximum control of these processes. This technology may be capable of sequencing >10(6) nucleotides per day per machine.