Plasmodium falciparum apicoplast transit peptides are unstructured in vitro and during apicoplast import

John R. Gallagher, Krista A. Matthews, Sean T. Prigge

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Trafficking of soluble proteins to the apicoplast in Plasmodium falciparum is determined by an N-terminal transit peptide (TP) which is necessary and sufficient for apicoplast import. Apicoplast precursor proteins are synthesized at the rough endoplasmic reticulum, but are then specifically sorted from other proteins in the secretory pathway. The mechanism of TP recognition is presently unknown. Apicoplast TPs do not contain a conserved sequence motif; therefore, we asked whether they contain an essential structural motif. Using nuclear magnetic resonance to study a model TP from acyl carrier protein, we found a short, low-occupancy helix, but the TP was otherwise disordered. Using an in vivo localization assay, we blocked TP secondary structure by proline mutagenesis, but found robust apicoplast localization. Alternatively, we increased the helical content of the TP through mutation while maintaining established TP characteristics. Apicoplast import was disrupted in a helical mutant TP, but import was then restored by the further addition of a single proline. We conclude that structure in the TP interferes with apicoplast import, and therefore TPs are functionally disordered. These results provide an explanation for the amino acid bias observed in apicoplast TPs.

Original languageEnglish (US)
Pages (from-to)1124-1138
Number of pages15
JournalTraffic
Volume12
Issue number9
DOIs
StatePublished - Sep 1 2011

Fingerprint

Apicoplasts
Plasmodium falciparum
Peptides
Proline
Acyl Carrier Protein
In Vitro Techniques
Mutagenesis
Protein Precursors
Rough Endoplasmic Reticulum
Conserved Sequence
Secretory Pathway
Protein Transport
Assays
Proteins
Magnetic Resonance Spectroscopy
Nuclear magnetic resonance

Keywords

  • Acyl carrier protein
  • Apicoplast
  • Malaria
  • Trafficking
  • Transit peptide

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Structural Biology
  • Molecular Biology
  • Genetics

Cite this

Plasmodium falciparum apicoplast transit peptides are unstructured in vitro and during apicoplast import. / Gallagher, John R.; Matthews, Krista A.; Prigge, Sean T.

In: Traffic, Vol. 12, No. 9, 01.09.2011, p. 1124-1138.

Research output: Contribution to journalArticle

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