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1Y13: Difference between revisions
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== ''Post scriptum'' == | == ''Post scriptum'' == | ||
In a discussion with Gerard Bricogne and Clemens Vonrhein after the ACA2011 workshop it turned out that my theory, which claims that E1 and E2 are actually the same wavelength, is wrong. This was investigated by looking at the difference map (obtained using phenix.fobs_minus_fobs_map) of E1 and E2 (taking the first ~370 frames in each case) phased with the 1y13 model, which shows three strong (14-19 sigma) peaks. The fact that the 1-370 pieces merge so well seems to be a consequence of the fact that the anomalous signal of the two wavelengths is so similar, and the dispersive difference between the wavelengths does not significantly decrease the high correlation coefficient in data scaling. | In a discussion with Gerard Bricogne and Clemens Vonrhein after the ACA2011 workshop it turned out that my theory, which claims that E1 and E2 are actually the same wavelength, is wrong. This was investigated by looking at the difference map (obtained using phenix.fobs_minus_fobs_map) of E1 and E2 (taking the first ~370 frames in each case) phased with the 1y13 model, which shows three strong (14-19 sigma) peaks. The fact that the 1-370 pieces merge so well seems to be a consequence of the fact that the anomalous signal of the two wavelengths is so similar, and the dispersive difference between the wavelengths does not significantly decrease the high correlation coefficient in data scaling. | ||
Thus the above describes a pseudo-SAD solution, and even better phasing would be obtained by keeping the wavelengths separate and doing MAD (in fact DAD) - but zero-dose extrapolation could and should be done in the same way. | Thus the above describes a pseudo-SAD solution, and even better phasing would be obtained by keeping the wavelengths separate and doing MAD (in fact DAD) - but zero-dose extrapolation could and should be done in the same way. I've therefore continued the analysis in [[1Y13-revisited]]. | ||