As mentioned there is no I/sigmaI rule. Also you need to specify (and correctly calculate) <I/sigmaI> and not <I>/<sigmaI>.
A review of similar articles in the same journal will show what is typical for the journal. I think you will find that the <I/sigmaI> cutoff varies. This information can be used in your response to the reviewer as in, "A review of actual published articles in the Journal shows that 75% (60 out of 80) used an <I/sigmaI> cutoff of 2 for the resolution of the diffraction data used in refinement. We respectfully believe that our cutoff of 2 should be acceptable." -----Original Message----- From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Roberto Battistutta Sent: Thursday, March 03, 2011 5:30 AM To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] I/sigmaI of >3.0 rule Dear all, I got a reviewer comment that indicate the "need to refine the structures at an appropriate resolution (I/sigmaI of >3.0), and re-submit the revised coordinate files to the PDB for validation.". In the manuscript I present some crystal structures determined by molecular replacement using the same protein in a different space group as search model. Does anyone know the origin or the theoretical basis of this "I/sigmaI >3.0" rule for an appropriate resolution? Thanks, Bye, Roberto. Roberto Battistutta Associate Professor Department of Chemistry University of Padua via Marzolo 1, 35131 Padova - ITALY tel. +39.049.8275265/67 fax. +39.049.8275239 roberto.battistu...@unipd.it www.chimica.unipd.it/roberto.battistutta/ VIMM (Venetian Institute of Molecular Medicine) via Orus 2, 35129 Padova - ITALY tel. +39.049.7923236 fax +39.049.7923250 www.vimm.it
