really fascinating, bringing back the discussion for a repository for your collected frames. Jürgen Acta Cryst. (2012). F68, 366-376 doi:10.1107/S1744309112008421http://dx.doi.org/10.1107/S1744309112008421 Detection and analysis of unusual features in the structural model and structure-factor data of a birch pollen allergen B. Rupphttp://scripts.iucr.org/cgi-bin/citedin?search_on=name&author_name=Rupp,%20B. Abstract: Physically improbable features in the model of the birch pollen structure Bet v 1d (PDB entry 3k78http://pdb.pdb.bnl.gov/pdb-bin/opdbshort?3k78) are faithfully reproduced in electron density generated with the deposited structure factors, but these structure factors themselves exhibit properties that are characteristic of data calculated from a simple model and are inconsistent with the data and error model obtained through experimental measurements. The refinement of the 3k78http://pdb.pdb.bnl.gov/pdb-bin/opdbshort?3k78model against these structure factors leads to an isomorphous structure different from the deposited model with an implausibly small R value (0.019). The abnormal refinement is compared with normal refinement of an isomorphous variant structure of Bet v 1l (PDB entry 1fm4http://pdb.pdb.bnl.gov/pdb-bin/opdbshort?1fm4). A variety of analytical tools, including the application of Diederichs plots, R plots and bulk-solvent analysis are discussed as promising aids in validation. The examination of the Bet v 1d structure also cautions against the practice of indicating poorly defined protein chain residues through zero occupancies. The recommendation to preserve diffraction images is amplified. ...................... Jürgen Bosch Johns Hopkins University Bloomberg School of Public Health Department of Biochemistry & Molecular Biology Johns Hopkins Malaria Research Institute 615 North Wolfe Street, W8708 Baltimore, MD 21205 Office: +1-410-614-4742 Lab: +1-410-614-4894 Fax: +1-410-955-2926 http://web.mac.com/bosch_lab/