Datensatz

Zusammenfassung

Structural biology is a new branch of basic research and avails oneself of knowledge from many other sciences like molecular biology, chemistry, biophysics and computer science. The goal of structural biology is a better understanding of biological processes at atomic resolution. To reconstruct proteins three different techniques do exist: X-ray crystallography, PNRM and single particle refinement. At the Karolinska Institute we developed a new method basing on single particle refinement combined with the knowledge we gain from the symmetric order of a crystal. Therefore we developed and implemented two new process steps for the well known reconstruction software EMAN2. The first process step improves the boxing tool - the cutting of single protein unit cells from the TEM image. The second step improves the refinement by
decreasing the number of possible Eularian angles.
To proof our results we tested the new software package on the sugar symporter MelB. The best resolution of MelB gained by single particle is 8Å [Purhonen: Three-dimensional
structure of the suger syporter. Journal of Structural Biology, 152:76-83, 2005]. Based on the first experiments and testings it seems that a resolution better than 6Å can be achieved with the same number of iterations and the same image set as used in the 8Å-refinement. The refinement process according to the less number of alignments is much faster now. About 40 of less time is necessary.