Hi All, This is a fairly basic question coming from a novice crystallographer, but I was wonder at what point it's reasonable to say 'I can't model that loop!'. I'm currently working on a couple of structures and there's density for where the a flexible loop on both structures goes, but there isn't good density for side chains (even aromatic ones) and even if the loop can be closed it doesn't seem like the Ramachandran plot will ever be happy. Both data sets are around 2A so it's not a question of poor density overall
I was wondering if there was a consensus for when density is unmodelable, or if there are any tips for fitting residues into poor density. Thanks in advance, Rhys Grinter PhD Candidate University of Glasgow
