A synthetic peptide study on the molten globule of alpha-lactalbumin.
We investigated the conformations of peptides that encompass the B helix or C helix region formed in the molten globule of bovine alpha-lactalbumin to get information on the molecular mechanism that stabilizes the molten globule. The CD spectra show that the isolated B and C helices are intrinsically unstable. The chemical shifts, NOE connectivities, and CD spectrum indicate that no helical structure is induced in the C helix region (86-99) by extending the peptide sequence to include the hydrophobic cluster region (101-107), although the hydrophobic cluster region can be regarded as a possible initiation site for folding of the protein. We also clarified that the isolated B helix (23-34) peptide does not directly interact with the C helix or hydrophobic cluster region. These results suggest that the B and C helices in the molten globule are stabilized by their interaction with other parts of the protein.
Shimizu
A
A
Department of Bioengineering, Faculty of Engineering, Soka University, Tokyo.
Ikeguchi
M
M
Kobayashi
T
T
Sugai
S
S
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002942:Circular Dichroism; D007768:Lactalbumin / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry*; D011487:Protein Conformation; D017433:Protein Structure, Secondary
D010455:Peptides; D007768:Lactalbumin