SEMI-AUTOMATED DENSITY FITTING WITH XTALVIEW. Duncan McRee, The Scripps Research Institute, 10666 N. Torrey Pines Rd., La Jolla, CA 92037, dem@scripps.edu

The newest release of XtalView from CCMS and MSI includes new features for semi-automated density fitting in XFIT. The program will search the density to find a likely position for the next C-alpha. Five alternatives are also found. The user can also use the mouse to adjust the C-alpha manually using a "baton". After a fragment is built it can be changed to poly-ala with by automated building of overlaaping penatamers. At this point the user can specify position in the amino acid sequence and the program mutates the side chains and find the rotamer with the highest overlap with the density. A number of features have been added to allow naming residues, reversing chains, sorting fragments, and adding chain ID's. The new version can be obtained from CCMS by sending email to ccms-request@sdsc.edu with a blank subject and the message 'get xtalview'.