C-terminal secretion signal of an Erwinia chrysanthemi protease secreted by a signal peptide-independent pathway: proton NMR and CD conformational studies in membrane-mimetic environments.
The detailed structure of a 68-residue chimeric peptide encompassing the 56 last C-terminal residues of Erwinia chrysanthemi protease G has been investigated by using circular dichroism and NMR spectroscopies. The peptide which contains the secretion signal of PrtG was solubilized either in aqueous solvent, in trifluoroethanol (TFE)/H2O mixtures, or in dodecyl beta-D-maltoside detergent. The peptide helical content increases upon TFE and detergent additions. A stable conformation is reached at 40% TFE (v:v) and at a micelle to peptide ratio higher than 1. The 1H NMR spectrum has been assigned in TFE/H2O, 2:1 (v:v), and it is shown that residues 26-29 and 50-62 form a relatively stable helix although a conformational equilibrium between a helix and probably a more random structure is observed throughout fragment 13-63. Comparison of the CterG conformation with results obtained by deletion approach could lead to the hypothesis that the C-terminal secretion signal is composed of an alpha-helix located close to the essential C-terminal tetrapeptide D65VIV.
Wolff
N
N
Laboratoire de Résonance Magnétique Nucléaire, CNRS URA 1129, Institut Pasteur, Paris, France.
Ghigo
J M
JM
Delepelaire
P
P
Wandersman
C
C
Delepierre
M
M
D000595:Amino Acid Sequence; D002942:Circular Dichroism; D016974:Dickeya chrysanthemi / Q000201:enzymology*; D009682:Magnetic Resonance Spectroscopy; D008666:Metalloendopeptidases / Q000737:chemistry* / Q000378:metabolism*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D001616:beta-Galactosidase / Q000737:chemistry
D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; D001616:beta-Galactosidase; D008666:Metalloendopeptidases; C086379:PrtG metalloprotease