Hi Julian, If I understand correctly, you have an NOE restraint to the OH proton of an aspartic acid residue. Then, the error likely stems from the fact that, by default, aspartic (and glutamic) acid is considered deprotonated in Xplor-NIH. That is, the proton currently doesn't exist in your system.
Although we are currently working on replacing the default Xplor-NIH residue library (the topology and parameters) by one where, among other things, specifying the protonation state of Asp and Glu will be straightforward, the current library needs some additions to handle this. Let me know if the above is your case. If so, we can provide parameters to generate the protonated versions of Glu and Asp. Best, Guillermo ######################################################################## To unsubscribe from the XPLOR-NIH list, click the following link: http://list.nih.gov/cgi-bin/wa.exe?SUBED1=XPLOR-NIH&A=1
