Structural features of a peptide corresponding to human kappa-casein residues 84-101 by 1H-nuclear magnetic resonance spectroscopy.
The peptide Val-Arg-Arg-Pro-Asn-Leu-His-Pro-Ser-Phe-Ile-Ala-Ile-Pro-Pro- Lys-Lys-Ile, which corresponds to residues 84-101 of human kappa-casein, has been synthesized and its conformation preferences determined by 1H-nuclear magnetic resonance spectroscopy in dimethyl sulphoxide. The peptide adopted a largely extended chain conformation in solution and there was evidence for the presence of a beta-turn involving residues Pro87-His90 of human kappa-casein. The presence of a turn in this position would make the physiologically significant Arg85 residue of human kappa-casein (which is equivalent to Arg97 in bovine kappa-casein) unavailable for interaction with Asp249 of bovine chymosin, and may partly explain why human kappa-casein is hydrolysed more slowly than its bovine counterpart by bovine chymosin.
Plowman
J E
JE
Wool Research Organisation of New Zealand, Christchurch, New Zealand.
Creamer
L K
LK
Liddell
M J
MJ
Cross
J J
JJ
D000595:Amino Acid Sequence; D000818:Animals; D001120:Arginine; D002364:Caseins / Q000737:chemistry*; D002417:Cattle; D004121:Dimethyl Sulfoxide; D006801:Humans; D006860:Hydrogen Bonding; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D010446:Peptide Fragments / Q000737:chemistry*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D012996:Solutions
D002364:Caseins; D010446:Peptide Fragments; D012996:Solutions; D001120:Arginine; D004121:Dimethyl Sulfoxide