The structural flexibility of the preferredoxin transit peptide.
In order to obtain insight into the structural flexibility of chloroplast targeting sequences, the Silene pratensis preferredoxin transit peptide was studied by circular dichroism and nuclear magnetic resonance spectroscopy. In water, the peptide is unstructured, with a minor propensity towards helix formation from Val-9 to Ser-12 and from Gly-30 to Ser-40. In 50% (v/v) trifluoroethanol, structurally independent N- and C-terminal helices are stabilized. The N-terminal helix appears to be amphipathic, with hydrophobic and hydroxylated amino acids on opposite sides. The C-terminal helix comprises amino acids Met-29-Gly-50 and is destabilized at Gly-39. No ordered tertiary structure was observed. The results are discussed in terms of protein import into chloroplasts, in which the possible interactions between the transit peptide and lipids are emphasized.
Department of Biochemistry of Membranes, Centre for Biomembranes and Lipid Enzymology, Institute of Biomembranes, Utrecht University, The Netherlands. h.l.j.wienk@chem.uu.nl
H L
HL
Wienk
M
M
Czisch
B
B
de Kruijff
D000595:Amino Acid Sequence; D001692:Biological Transport; D002736:Chloroplasts / Q000378:metabolism*; D005288:Ferredoxins / Q000737:chemistry*; D019684:Magnoliopsida; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D010940:Plant Proteins / Q000737:chemistry; D018583:Pliability; D011498:Protein Precursors / Q000737:chemistry*; D021382:Protein Sorting Signals / Q000737:chemistry*; D017433:Protein Structure, Secondary; D012997:Solvents; D014270:Trifluoroethanol; D014867:Water
D005288:Ferredoxins; D010940:Plant Proteins; D011498:Protein Precursors; D021382:Protein Sorting Signals; D012997:Solvents; D014867:Water; C085169:preferredoxin; D014270:Trifluoroethanol