Hi, Inbal! Just for your information, although modeling programs might construct theoretical models and compute atomic coordinates with 5-point precision, no atomic coordinates from experimental structure determination (crystallography or NMR) are known to 5-point precision. Even three decimal places greatly overstates the certainty of atomic positions in experimental models. For experimental macromolecular models at the highest resolution, if coordinates are expressed in angstroms, the first decimal place (tenths of angstroms) is the last significant digit, and thus it is uncertain (plus or minus 0.1 to 0.3 angstroms), while subsequent digits are meaningless. Uncertainty in atomic positions in the best experimental macromolecular models is usually not less than 0.1 angstrom. In most published models, it is higher. In addition, uncertainty in atomic positions is not the same in all parts of an experimental model. And finally, these numbers treat the model as static, which is certainly not true. The coordinates are best viewed as centroids of motion, not as fixed positions. As a rule of thumb, I consider any intramolecular measurement on even the best macromolecular model to be uncertain by 0.1 to 0.2 angstroms. In crystallographic models, uncertainty in atomic positions is not the same as stated model resolution, which has to do with the highest angle at which reliable data were collected. Tolerance or uncertainty in atomic positions can be estimated from measures of data quality in various resolution ranges. Graphics pictures of macromolecular models convey a misleading sense of certainty about atomic locations. Some (a small percentage, but too many) of models in PDB are of very low quality and reliability. Just because a model is in the PDB does not mean it is a high quality model. For an enlightening (and startling) introduction to judging the quality of macromolecular models, see Gerard Kleywegt's excellent structure validation tutorials at http://xray.bmc.uu.se/gerard/embo2001/modval/index.html Cheers! On Mar 8, 2005, at 12:48 AM, Inbal Tuvi-Arad wrote: > Hello all, > Does anyone know how can I convert xyz files that have 5 decimal point > precision to pdb files without loosing the precision? All my attempts > to > use conversion programs or Website creates pdb files with only 3 > decimal > point precision. > > Sincerely, > > Inbal Tuvi-Arad > > __________________________________ > Dr. Inbal Tuvi-Arad > Department of Natural Sciences > The Open University of Israel > 108 Ravutski St., POB 808, > Raanana, 43107, Israel > Tel: 972-9-778-1773 > Fax: 972-9-778-0661 > Email: inbaltu at openu.ac.il > __________________________________ > > _______________________________________________ > Molvis-list mailing list > Molvis-list at bioinformatics.org > https://bioinformatics.org/mailman/listinfo/molvis-list > > Gale Rhodes, Professor of Chemistry University of Southern Maine PO Box 9300 Portland, Maine 04104-9300 http://www.usm.maine.edu/~rhodes