[ccp4bb] Truncation of first two residues "rescued" an insoluble protein?

Dear all, Sorry for the off-topic question, but I am really curious why two terminal residues could make such huge difference. I am working on a all helical domain starting from residue 1 to about 130. It expressed well with N-terminal His tag in both E.Coli and insect cell, but stayed in

[ccp4bb] ERROR: can't read "array(ef2ccp4)": no such element in array

16) invoked from within "SwitchProject fabz .module.mesbar.switchProj.m" (menu invoke) Could anyone tell me how to fix it? Thanks in advance! Tiancen Hu Shanghai Institute of Materia Medica

[ccp4bb] Summary: recommendation for heavy atoms used in lithium sulfate and ammonium sulfate

Thanks for the quick and instructive replies. This is my original question: Could any one recommend some heavy atoms used for crystals grown in 0.1M tri-sodium citrate pH 5.6, 1M Lithium sulfate and 0.5M ammonium sulfate? I read from Hampton user guide of heavy atom kit that "high salt concentra

[ccp4bb] recommendation for heavy atoms used in lithium sulfate and ammonium sulfate

with macromolecules", so is there any type of heavy atom we should avoid using? We do not have any experience in preparing heavy atom derivative, so any suggestions, experience or references will be greatly appreciated. Thanks in advance! Tiancen Hu Shanghai Institute of Materia Medica

[ccp4bb] Fancy crystal, poor diffraction

truncated ones, complexed with its ligands etc. I believe many protein crystallographers have encountered similar problems, are there any successful stories from these fancy poor crystals? Any suggestions or references will be highly appreciated. Thanks in advance! Tiancen Hu Shanghai