The apicoplast is a distintive subcellular structure, acquired when an ancestral protist
'ate' (or was invaded by) a eukaryotic alga, and retained the algal plastid. The apicoplast
has lost photosynthetic function, but is nevertheless essential for parasite survival, and
has generated considerable excitement as a potential drug target. Nuclear-encoded apicoplast
proteins are imported into the organelle using a bipartite targeting signal consisting of a
classical secretory signal sequence, followed by a plastid transit peptide.
PlasmoAP is a rules-based algorithm that uses amino-acid frequency and distribution to identify
putative apicoplast-targeting peptides. Just paste a protein sequence into the text box
above, and click on "Run". Note that this algorithm will predict target to the apicoplast
only if a signal sequence is present. Also note that PlasmoAP performs well only
for P. falciparum sequences, as A+T content skews amino acid distribution.
For more information on this tool please
here, or see Foth, BJ et al. Science 299:5606 (2003).