P1 Shake-and-Bake: can success be guaranteed?
The multi-trial direct-methods procedure known as Shake-and-Bake has been applied to three small proteins (alpha-1 peptide, vancomycin and lysozyme) that crystallize in space group P1. Phase refinement was accomplished through parameter-shift optimization using both the cosine and exponential forms of the minimal function. By extending error-free data to sufficiently high resolution, 100% convergence of trial structures to solution could be achieved in all three cases by using the exponential minimal function and a shift angle in the range 130-150 degrees. These results suggest optimum parameters for other P1 structures and emphasize the importance of collecting data to the highest possible resolution.
Xu
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Hauptman-Woodward Medical Research Institute, 73 High Street, Buffalo, NY 14203, USA. xu@hwi.buffalo.edu
Hauptman
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HA
Weeks
C M
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Miller
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D000465:Algorithms; D003460:Crystallization; D018360:Crystallography, X-Ray / Q000379:methods*; D009113:Muramidase / Q000737:chemistry; D011506:Proteins / Q000737:chemistry*; D014640:Vancomycin / Q000737:chemistry
D011506:Proteins; D014640:Vancomycin; D009113:Muramidase