Conformation and interactions of uteroglobin fragments 4-14 and 49-65 in aqueous solution containing surfactant micelles.
The conformation of two fragments of rabbit uteroglobin is described. The peptides are PRFAHVIENLL and PQTTRENIMKLTEKIVK, corresponding to helices I and IV in the crystal structure. CD shows that both peptides interact with sodium dodecyl sulfate (SDS) micelles and change their conformation to an alpha-helix. The helical content estimated from the CD band at 222 nm is about 40% in each peptide. Surface tension measurements show that both peptides lower the critical micellar concentration (cmc) of SDS, with a more dramatic effect in the case of helix I. This peptide by itself acts as a surfactant, and is able to interact with SDS even below the observed cmc, forming beta aggregates. Proton magnetic resonance (1H-nmr) suggests that flexible helices are present. The longest helical stretches compatible with 1H-nmr data extend from Phe6 to Leu14 for helix I and from Arg53 to Ile63 for helix IV.
Tessari
M
M
Department of Organic Chemistry, University of Padova, Italy.
Foffani
M T
MT
Mammi
S
S
Peggion
E
E
D000595:Amino Acid Sequence; D000818:Animals; D005260:Female; D008823:Micelles; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry*; D011487:Protein Conformation; D011817:Rabbits; D012996:Solutions; D013501:Surface-Active Agents / Q000737:chemistry*; D014598:Uteroglobin / Q000737:chemistry*; D014867:Water
D008823:Micelles; D010446:Peptide Fragments; D012996:Solutions; D013501:Surface-Active Agents; D014867:Water; D014598:Uteroglobin