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The DNA binding parvulin Par17 is targeted to the mitochondrial matrix by a recently evolved prepeptide uniquely

Daniel Kessler1, Panagiotis Papatheodorou, Tina Stratmann

  • 1Department of Structural and Medicinal Biochemistry, Center for Medical Biotechnology - ZMB, University of Duisburg-Essen, 45117 Essen, Germany. daniel.kessler@uni-due.de

BMC Biology
|September 19, 2007
PubMed
Abstract

Insights

The newly discovered parvulin Par17, found in humans but not other mammals, targets the mitochondrial matrix. This DNA-binding protein represents a novel component of the human mitochondrial proteome.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Evolutionary Biology

Background:

  • Parvulin-type peptidyl prolyl cis/trans isomerase Par14 is highly conserved across metazoans.
  • The recently identified parvulin Par17 possesses a unique N-terminal domain, prompting investigation into its evolutionary occurrence and functional role.

Purpose of the Study:

  • To investigate the evolutionary presence and subcellular localization of parvulin Par17.
  • To determine the functional characteristics of Par17, including its mitochondrial targeting and DNA-binding capabilities.

Main Methods:

  • Genomic analysis of Par17 exon sequences across 10 primate species.
  • Subcellular fractionation and immunofluorescence microscopy of human cell lysates.
  • Mitochondrial import assays and DNA-binding assays under varying salt conditions.

Main Results:

  • Par17 is encoded in Hominidae genomes (including humans) but absent in other mammalian species studied.
  • Endogenous Par17 localizes to mitochondria and membrane fractions, with EGFP fusions co-localizing with mitochondrial markers.
  • Par17 exhibits salt-resistant association with mitochondria, is imported into the mitochondrial matrix dependent on membrane potential, and binds double-stranded DNA.

Conclusions:

  • Parvulin Par17 is a DNA-binding protein specifically targeted to the mitochondrial matrix.
  • Its mitochondrial targeting is mediated by a recently evolved mitochondrial prepeptide.
  • Par17 represents a novel protein constituent of the Hominidae mitochondrial proteome.

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