TABLE 1.

Important features of type III and type IV secretion signalsa

Important featureIdentification by:
Arnold et al. (4)Löwer and Schneider (41)Samudrala et al. (65)Burstein et al. (9)Previous observations
Positional sequence patternNoYesaYesYesYes
Disordered structural motifYesYesYes
Charged residue biasesYesYesaYesYes
Serine/threonine biasYesYesaYesYes
Proline biasYesYesaNoNo
Hydrophobic biasYesYesaYesYes
Terminal 20 to 30 residues importantYesYesYesYesYes
G+C gene content biasYesYesYes
Taxonomic distributionYesYesYes
  • a The study results implied the indicated importance but did not specifically call it out.