Inferred phylogenetic relationships among the A. ferrooxidans and closely related bacterial sHSPs. The 20 closest related bacterial protein sequences to each A. ferrooxidans sHSP were retrieved by a BLAST search against 1295 completed bacteria genomes (see Methods section). The topology was obtained by ML using 76 aligned amino acids residues. Distances were calculated by PAM matrix and the statistical confidence of the nodes was calculated by aLRT test. Branches with aLRT values lower than 50% were collapsed. GeneBank accession numbers are shown in front of the species name.