PT - JOURNAL ARTICLE AU - Martin Steinegger AU - Markus Meier AU - Milot Mirdita AU - Harald Vöhringer AU - Stephan J. Haunsberger AU - Johannes Söding TI - HH-suite3 for fast remote homology detection and deep protein annotation AID - 10.1101/560029 DP - 2019 Jan 01 TA - bioRxiv PG - 560029 4099 - http://biorxiv.org/content/early/2019/02/25/560029.short 4100 - http://biorxiv.org/content/early/2019/02/25/560029.full AB - Background HH-suite is a widely used open source software suite for sensitive sequence similarity searches and protein fold recognition. It is based on pairwise alignment of profile Hidden Markov models (HMMs), which represent multiple sequence alignments of homologous sequences.Results We developed a single-instruction multiple-data (SIMD) vectorized implementation of the Viterbi algorithm for profile HMM alignment and introduced various other speed-ups. This accelerated HHsearch by a factor 4 and HHblits by a factor 2 over the previous version 2.0.16. HHblits3 is ~10× faster than PSI-BLAST and ~20× faster than HMMER3. Jobs to perform HHsearch and HHblits searches with many query profile HMMs can be parallelized over cores and over servers in a cluster using OpenMP and message passing interface (MPI). The free, open-source, GNU GPL(v3)-licensed software is available at https://github.com/soedinglab/hh-suite.Conclusion The added functionalities and increased speed of HHsearch and HHblits should facilitate their use in large-scale protein structure and function prediction, e.g. in metagenomics and genomics projects.MSA:multiple sequence alignment;HMM:hidden Markov model;SIMD:single-instruction multiple-data;SSSE3:supplemental streaming SIMD extensions 3;AVX2:advanced vector extension (SIMD instruction set standards);