Re: [ccp4bb] electron density slabs

Slabs are almost always due to rogue huge reflection(s). If you run mtzdump on the refmac_output.mtz you will find the maximum value and average value of each column. If you run fft hklin refmac_output.mtz LABI F1=FWT PHI=PHWT then the log file gives you the indices of the largest reflection

[ccp4bb] Fwd: [ccp4bb] electron density slabs

This could be due to biscuit contamination of your protein - did you eat cake before setting up your crystallisation drops?Alternatively it could be a Fourier ripple - a very strong 5.4 Å resolution 00l reflection which is not correctPoulBegin forwarded message:From: hayato Jumonji

[ccp4bb] electron density slabs

Dear all, I've phased 3 wavelength SeMet dataset with SHELX and the resulting mtz on Coot shows ~5.4 A apart slabs in water channel. I've captured part of the electron density at 0.4sigma. The slabs appear through out the electron density and parallel to AB plane (space group P21212). Most of the