title: Eukaryotic peptide deformylases. Nuclear-encoded and chloroplast-targeted enzymes in Arabidopsis.
abstract: Arabidopsis (ecotype Columbia-0) genes, AtDEF1 and AtDEF2, represent eukaryotic homologs of the essential prokaryotic gene encoding peptide deformylase. Both deduced proteins contain three conserved protein motifs found in the active site of all eubacterial peptide deformylases, and N-terminal extensions identifiable as chloroplast-targeting sequences. Radiolabeled full-length AtDEF1 was imported and processed by isolated pea (Pisum sativum L. Laxton's Progress No. 9) chloroplasts and AtDEF1 and 2 were immunologically detected in Arabidopsis leaf and chloroplast stromal protein extracts. The partial cDNAs encoding the processed forms of Arabidopsis peptide deformylase 1 and 2 (pAtDEF1 and 2, respectively) were expressed in Escherichia coli and purified using C-terminal hexahistidyl tags. Both recombinant Arabidopsis peptide deformylases had peptide deformylase activity with unique kinetic parameters that differed from those reported for the E. coli enzyme. Actinonin, a specific peptide deformylase inhibitor, was effective in vitro against Arabidopsis peptide deformylase 1 and 2 activity, respectively. Exposure of several plant species including Arabidopsis to actinonin resulted in chlorosis and severe reductions in plant growth and development. The results suggest an essential role for peptide deformylase in protein processing in all plant plastids.
authors.affiliation: Department of Horticulture, N-323 Agricultural Science Center North, University of Kentucky, Lexington, Kentucky 40546-0091, USA.
authors.forename: L M
authors.initials: LM
authors.lastname: Dirk
authors.forename: M A
authors.initials: MA
authors.lastname: Williams
authors.forename: R L
authors.initials: RL
authors.lastname: Houtz
mesh_terms: D000581:Amidohydrolases; D000595:Amino Acid Sequence; D000626:Aminopeptidases / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D015153:Blotting, Western; D002467:Cell Nucleus / Q000235:genetics*; D002736:Chloroplasts / Q000201:enzymology* / Q000235:genetics; D003001:Cloning, Molecular; D004926:Escherichia coli; D006877:Hydroxamic Acids / Q000494:pharmacology; D007700:Kinetics; D008969:Molecular Sequence Data; D018532:Pisum sativum / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics
chemical_list: D006877:Hydroxamic Acids; D000626:Aminopeptidases; D000581:Amidohydrolases; C084507:peptide deformylase; C010531:actinonin