Reduce

Reduce is a program for adding hydrogens to a Protein DataBank (PDB) molecular structure file. Hydrogens are added in standardized geometry with optimization of the orientations of OH, SH, NH₃⁺, Met methyls, Asn and Gln sidechain amides, and His rings. Both proteins and nucleic acids can be processed. HET groups can also be processed as long as the atom connectivity is provided. A slightly modified version of the connectivity table published by the PDB is available below. The program is described in Word, et al.(1999) "Asparagine and glutamine: using hydrogen atom contacts in the choice of sidechain amide orientation" J. Mol. Biol. 285, 1735-1747. (doi.org/10.1006/jmbi.1998.2401)