Dear Dr. Bryce, during my PhD research I concentrated on MD simulations with AMBER 7 on HIV protease and its inhibitors. I would like to contribute parameters for all moieties of two clinically used inhibitors, saquinavir (SQV) and indinavir (IDV). PREPs: as attachment, P? means standard nomenclature of moieties FRCMODs: attached in the following e-mail Citation: *Lepaík M*, Kr(í~ Z, Havlas Z. Efficiency of a second-generation HIV-1 protease inhibitor studied by molecular dynamics and calculations of absolute binding free energies. *Proteins* 2004;57:279-293. Comments: The parameters were taken from gaff force field for use with parm99 AMBER protein force field. Crystal geometries of PR-bound inhibitors were used. Single conformation fitting to HF/6-31G* ESP was applied. ---- I would be grateful if you could add these parameters to the AMBER database. Yours sincerely, Martin Lepsik ------------------ Martin Lepsik, Ph.D. Center for Complex Molecular Systems and Biomolecules, Institute of Organic Chemistry & Biochemistry, Czech Rep. Flemingovo nam. 2, 166 10, Praha 6 phone: +420-220 410 318 e-mail:lepsik@uochb.cas.cz