> 2 4 order. I have got one isotope mismatch error message. I looked > through and found a peak in 3dNnoesy which contained the culprit > resonance. The peak assignment > reads:Leu75H-(Cys76N/Trp33Cz2)-(Cys76H/Trp33Hz2). So, this time Analysis > did not drop wrong nuclei and I've got C in Nnoesy.Hope this helps. This does help, and is all consistent with my latest inquiry. Thanks. The merged peak theory is still upper most in my mind; it must be an issue that is sporadic and only affects a small proportion of peaks. If only ARIA had a good data model like CCPN; then there would be no problem in knowing which dim was which, even if 13C and 15 N NOESY peaks were merged into one... Next week I will post some diagnostics, if not a fix. T.x ------------------------------------------------------------------------------- Dr Tim Stevens Email: [log in to unmask] Department of Biochemistry [log in to unmask] University of Cambridge Phone: +44 1223 766018 (office) 80 Tennis Court Road +44 7816 338275 (mobile) Old Addenbrooke's Site +44 1223 364613 (home) Cambridge CB2 1GA WWWeb: http://www.bio.cam.ac.uk/~tjs23 United Kingdom http://www.pantonia.co.uk ------------------------------------------------------------------------------- ------ +NH3CH(CH(CH3)OH)C(O)NHCH(CH(CH3)CH2CH3)C(O)NHCH(CH2CH2SCH3)CO2- ------- -------------------------------------------------------------------------------