SEQUENCING OF DNA BY LASER IONIZATION

我们建议开发一种快速的单链DNA测序方法 通过反射飞行时间质谱法测定寡聚体和多肽， 使用激光解吸、激光电离和激光控制 碎片化DNA片段的解吸已经沉积在一个 冷冻溶液或固体基质将研究脉冲红外 (IR)和紫外（UV）激光解吸。脱附的分子 中性电荷将在表面上方被真空紫外线电离 (VUV)激光束，导致单光子电离;另一种选择 比较的方法将是使用紫外激光，导致 多光子电离使用附加激光器进行可变破碎 光束将作为该激光器的波长、功率 密度和时间关系的电离激光器的最大 控制获得简单可靠的碎片模式， 序列赋值脱附激光参数的影响 碎片也将被检查。实验的目的是 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.