Dear All, I observed an issue with the alignment function of Chimera. I loaded a crystal structure where in between a loop is not modelled due to low electron density- so these residues are missing in the structure and the numbering also has this gap. When I align this structure with others, the missing residues are not recognized and chimera just overrides the numbering so after this loop all the numbers in the alignment do not fit anymore to the residues they should belong to although the structure and numberings are shown in the right way in the graphics window. How can I overcome this issue? Should I change the pdb-file? In which way? Thanks for all responses! -- Gesa Volkers Institut für Biochemie, Molekulare Strukturbiologie Felix-Hausdorff-Straße 4 17489 Greifswald Germany +49 (3834)-864392