Dear Chimera Developers, I am struggling with the overexpression and purification of a cytoplasmic protein that looks to be soluble only in a very narrow pH range. I know the average isoelectric point of the whole protein, but there would be much more informative, to know what is the average isoelectric point of the proteins solvation shell, I think. Therefore I modeled the 3D structure of the protein and I tried several other visualization programs to calculate this pI value, but I was not successful. Could you tell me please, if there is any option to make this estimation in Chimera? Thank you very much in advance! Best regards, Csaba Nagy ------------------------------- Csaba I. Nagy, PhD Postdoctoral Researcher, PharmaCity, Itäinen Pitkäkatu 4 C, 6th floor, room 6049 Molecular Plant Biology University of Turku FI-20014 TURKU, Finland Phone +358 2 333 7914 Fax +358 2 333 8075 Email  csaba.nagy@utu.fi --------------------------------