Carboxyl-terminal sequences influence the import of mitochondrial protein precursors in vivo.
The large subunit of carbamoyl phosphate synthase A [carbon-dioxide: L-glutamine amido-ligase (ADP-forming, carbamate-phosphorylating), EC 6.3.5.5] from Neurospora crassa is encoded by a nuclear gene but is localized in the mitochondrial matrix. We have utilized N. crassa strains that produce both normal and carboxyl-terminal-truncated forms of carbamoyl phosphate synthase A to ask whether the carboxyl terminus affects import of the carbamoyl phosphate synthase A precursor. We found that carboxyl-terminal-truncated precursors were directed to mitochondria but that they were imported less efficiently than full-length proteins that were synthesized in the same cytoplasm. Our results suggest that effective import of proteins into mitochondria requires appropriate combinations of targeting sequences and three-dimensional structure.
D000595:Amino Acid Sequence; D002223:Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing) / Q000096:biosynthesis / Q000235:genetics*; D007700:Kinetics; D008025:Ligases / Q000235:genetics*; D008928:Mitochondria / Q000201:enzymology*; D009154:Mutation; D009491:Neurospora / Q000235:genetics*; D009492:Neurospora crassa / Q000201:enzymology / Q000235:genetics*; D011499:Protein Processing, Post-Translational
D008025:Ligases; D002223:Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing)