Identification of eukaryotic parvulin homologues: A new subfamily of peptidylprolyl cis-trans isomerases

We report here the existence of a subfamily of eukaryotic parvulin proteins that have strong sequence homology with E. coli parvulin, but lack the WW do. main found in previously described eukarytoic parvulins. We hence term members of this subfamily EPVH (eukaryotic parvulin homologue). We describe the characterisation of hEPVH (human eukaryotic parvulin homologue). Immun ogold labelling transmission electron microscopy reveals that hEPVH is pref erentially localised in the mitochondrial matrix. The homology of hEPVH wit h its prokaryotic ancestor supports the hypothesis that this protein may ha ve a mitochondrial function. An essential role in this organelle may explai n the need for a high degree of conservation of this protein between distan tly related species. (C) 1999 Academic Press.