Oldfield Thomas J
Accelrys Inc., Department of Chemistry, University of York, Heslington, York YO10 5DD, England.
Acta Crystallogr D Biol Crystallogr. 2003 Mar;59(Pt 3):483-91. doi: 10.1107/s0907444902023570. Epub 2003 Feb 21.
The tracing of experimental electron maps in the field of protein crystallography is not a rate-limiting step for structure elucidation, but does represent the process that requires the most expertise and user time. This paper presents a method for automatically tracing the electron-density maps of proteins which can reliably generate a C(alpha) trace for protein maps with data in the resolution range 1.5-4 A. The number of C(alpha) atoms placed and the precision of atom placement depends on the quality of the map, but even with poor maps (FOM approximately 0.5) the algorithm can provide a significant saving in time over conventional methods of interpretation. The interpretation of six experimental maps is presented at different resolutions and levels of phase error; these show that data with an FOM of 0.7 or better can be entirely traced with no user intervention.
在蛋白质晶体学领域中，实验电子密度图的追踪并非结构解析的限速步骤，但它确实是最需要专业知识和用户时间的过程。本文提出了一种自动追踪蛋白质电子密度图的方法，该方法能够在分辨率范围为1.5 - 4埃的数据下，可靠地生成蛋白质图谱的Cα追踪。放置的Cα原子数量和原子放置精度取决于图谱质量，但即使对于质量较差的图谱（FOM约为0.5），该算法相较于传统解释方法也能显著节省时间。本文展示了对六个不同分辨率和相位误差水平的实验图谱的解释；这些结果表明，FOM为0.7或更高的数据无需用户干预即可完全追踪。
