Structural elements of the mitochondrial preprotein-conducting channel Tom40 dissolved by bioinformatics and mass spectrometry

►Phylogenetic and structural insights into Tom40. ►By biochemical and bioinformatic means Tom40 is assigned as 19-stranded β-barrel. ►Intra-pore helix is positioned by a conserved helix anchor region at the pore wall. ►Tom40-specific polar slide inside the pore maybe involved in pre-protein recognition. ►Conserved pore surface regions explain TOM assembly and TOM-TIM bridging mutants.