Progress in multidimensional NMR investigations of peptide and protein 3-D structures in solution. From structure to functional aspects.
2-D and 3-D NMR techniques were used to investigate the conformations in solution of several peptides and proteins for which crystalline structures are not available yet. Insect defensin A is a small (40 aa) antibiotic protein exhibiting a characteristic 'loop-helix-beta-sheet' structure. A striking analogy was found with charybdotoxin, a scorpion toxin in which a CSH (cysteine stabilized alpha-helix) motif is also present. Wheat phospholipid transfer protein (PLTP) (90 aa) has a 3-D structure resulting from the packing of four helices and of a C-terminal less well-defined fragment. Preliminary results show that PLTP forms a complex with lyso-PC and that such an interaction results in a conformational change affecting principally the C-terminal half of the protein. A last example is given with surfactin, a lipopeptide biosurfactant from bacterial origin. Its protonated form shows a very compact structure in which the two acidic residues located on the top of a 'horse saddle' topology face each other, whereas the ionized form could adopt a more extended conformation. A common property of these compounds is their capacity to interact with lipids. The present structural data open the way for a further establishment of structure-activity relationships.
Bonmatin
J M
JM
Centre de Biophysique Moléculaire (CNRS), Orléans, France.
Genest
M
M
Petit
M C
MC
Gincel
E
E
Simorre
J P
JP
Cornet
B
B
Gallet
X
X
Caille
A
A
Labbé
H
H
Vovelle
F
F
D000595:Amino Acid Sequence; D000890:Anti-Infective Agents / Q000737:chemistry; D001426:Bacterial Proteins / Q000737:chemistry; D002352:Carrier Proteins / Q000737:chemistry; D023082:Defensins; D007301:Insect Hormones / Q000737:chemistry*; D055666:Lipopeptides; D009682:Magnetic Resonance Spectroscopy; D008565:Membrane Proteins / Q000737:chemistry; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D010456:Peptides, Cyclic; D049294:Phospholipid Transfer Proteins; D010940:Plant Proteins / Q000737:chemistry; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry*; D012996:Solutions; D013329:Structure-Activity Relationship; D013501:Surface-Active Agents / Q000737:chemistry
D000890:Anti-Infective Agents; D001426:Bacterial Proteins; D002352:Carrier Proteins; D023082:Defensins; D007301:Insect Hormones; D055666:Lipopeptides; D008565:Membrane Proteins; D010455:Peptides; D010456:Peptides, Cyclic; D049294:Phospholipid Transfer Proteins; D010940:Plant Proteins; D011506:Proteins; D012996:Solutions; D013501:Surface-Active Agents; C058181:insect defensin A; C009365:surfactin peptide