title: Evidence for a link between translocation and processing during protein import into soybean mitochondria.
abstract: The effect of metal chelators on protein import was investigated using isolated soybean mitochondria and soybean precursor proteins. Adding 1,10-phenanthroline, a metal chelator that can cross both mitochondrial membranes abolished import of both the alternative oxidase, and the F(A)d subunit of the ATP synthase, a matrix located protein. Other metal chelators such as EDTA, 1,7-phenanthroline and 4,7-phenanthroline, which cannot cross the mitochondrial membranes, had no effect on import. When processing, a known metal-dependent step inside mitochondria, was inhibited using a mutagenesis approach (changing a -2 arginine to a -2 glycine in the pre-piece of the precursor), so was import. Thus it would appear that in soybean, at least, translocation of proteins across the mitochondrial membrane, as well as processing, relies on a metal dependent step. Taken together, the data suggest the two processes may be directly connected in these mitochondria.
authors.affiliation: Department of Biochemistry, University of Western Australia, Nedlands, Perth, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Whelan
authors.forename: M R
authors.initials: MR
authors.lastname: Tanudji
authors.forename: M K
authors.initials: MK
authors.lastname: Smith
authors.forename: D A
authors.initials: DA
authors.lastname: Day
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001692:Biological Transport / Q000187:drug effects; D002614:Chelating Agents / Q000494:pharmacology; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009154:Mutation; D010088:Oxidoreductases / Q000378:metabolism; D010618:Phenanthrolines / Q000494:pharmacology; D010940:Plant Proteins / Q000378:metabolism*; D011498:Protein Precursors / Q000378:metabolism; D011499:Protein Processing, Post-Translational / Q000502:physiology*; D006180:Proton-Translocating ATPases / Q000737:chemistry / Q000378:metabolism; D013025:Glycine max / Q000378:metabolism; D000099188:Alternative Oxidase
chemical_list: D002614:Chelating Agents; D024101:Mitochondrial Proteins; D010088:Oxidoreductases; D010618:Phenanthrolines; D010940:Plant Proteins; D011498:Protein Precursors; D006180:Proton-Translocating ATPases; D000099188:Alternative Oxidase; C025205:1,10-phenanthroline