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ISa: Difference between revisions
→Practical considerations: APS/22-ID is not J. Holton's beamline
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I have seen values around 15-20 for good crystals that allowed me to solve a MAD structure, but that required high multiplicity of observations. Values around 30 allowed me to solve a sulfur-SAD structure at medium resolution (diffraction to 2.3 A, anomalous signal to 3 A). | I have seen values around 15-20 for good crystals that allowed me to solve a MAD structure, but that required high multiplicity of observations. Values around 30 allowed me to solve a sulfur-SAD structure at medium resolution (diffraction to 2.3 A, anomalous signal to 3 A). | ||
I have also seen a value around 40 for Z. Dauter's 0.98A Proteinase K (2ID8) sulfur-SAD data from | I have also seen a value around 40 for Z. Dauter's 0.98A Proteinase K (2ID8) sulfur-SAD data from the APS/22-ID beamline, and recently even higher values were obtained at the SLS, beamline X06SA, with a Pilatus detector. | ||
On the other hand, I have sometimes obtained values less than 10 with good test crystals, clearly indicating strong systematic errors. It is always good to discuss this with the people who are responsible for the beamline. They might know what is broken, or might be able to find out what went wrong. | On the other hand, I have sometimes obtained values less than 10 with good test crystals, clearly indicating strong systematic errors. It is always good to discuss this with the people who are responsible for the beamline. They might know what is broken, or might be able to find out what went wrong. | ||