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> I have updated my Analysis and run Problem Resonances on the project (no any > spectra). Indeed, LeuCda* (or Cdb*) is no longer linked to both Hda* and > Hdb*, but it is linked to Cg only. Thus, Hd and Cd of Leu do not get linked > at all and the same goes for Val Cg and Hg. This is as it should be! These are ambiguous prochirals, and so the links cannot be made between them unless there is experimental evidence, i.e. to tie one shift to another. Considering Leu; CDa and CDb both point to CD1 and CD2, likewise HDa* and HDb* to both HD1* and HD2* (i.e. stereospecifically ambiguous). If it is not known if CDa resonance is really CD1 or CD2 then you cannot tie it to a particular H resonance, that is until you see the interaction between two resonances in the form of a peak with the right dims. Until an unambiguous bound relationship can be established between prochiral H & C resonances the a/b labels are independent (and default to up/down field). T. ------------------------------------------------------------------------------- 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- ------- -------------------------------------------------------------------------------