The blastx program finds alignments between the three-frame translations of a nucleotide sequence and protein sequences from an input database. In the OOF version of this program, the query sequence frames can be shifted within one alignment. The algorithm and low-level alignment functions were written by Zheng Zhang. They were incorporated into regular BLAST API by Sergei Shavirin. XML and tabular output are not yet implemented for the OOF alignments.