Hi Scott, 26 letters + 10 numbers = this is how many PDB file format can accommodate since altloc id field is one character long. However, phenix.refine does not have an upper limit. Once we all happily migrate to mmCIF one day this artificial limitation will go away. Pavel On 12/17/14 8:20 AM, Scott Horowitz wrote:

Hi all,

Does anyone happen to know the upper limit on the number of alternate conformations that phenix.refine can handle at once for a residue? From playing around with it, it seems that phenix.refine recognizes both letters and numbers in that position, but not a pound sign, so that would suggest it could at least handle 36, so long as I don't crash my computer trying that many. Is this correct, from anyone's experience/knowledge?

Thanks, Scott