Folding of aminosuccinyl peptides: thermodynamic data from temperature dependent circular dichroism measurements.
The conformational equilibrium of aminosuccinyl peptides between extended conformations and an intramolecularly hydrogen bonded type II' beta-turn conformation has been studied on the peptide Boc-L-Asu-Gly-L-Ala-OMe (Asu = aminosuccinyl residue) by means of temperature dependence of circular dichroism spectra. Owing to the peculiar chiroptical and conformational properties of the Asu residue, this technique proved to be very useful for deriving thermodynamic data for the above folding process. The value of delta H0 (-6.6 kJ mol-1), obtained for the peptide studied in a chloroformacetonitrile mixture, shows that the lower energy of the folded conformer is primarily due to the characteristic intramolecular hydrogen bond of the beta turns.
Capasso
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S
Centro di Studio di Biocristallografia, CNR, Facoltà di Scienze Ambientali, Seconda Università degli Studi di Napoli, Italy.
Mazzarella
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L
Zagari
A
A
D000595:Amino Acid Sequence; D002942:Circular Dichroism; D004151:Dipeptides / Q000737:chemistry*; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D012997:Solvents; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics; D014961:X-Ray Diffraction
D004151:Dipeptides; D012997:Solvents; C098472:tert-butyloxycarbonyl-aminosuccinyl-glycyl-alanine methyl ester