TY - JOUR
T1 - Colloidal calcium phosphate in the reconstituted milk micelle may direct wild-type recombinant human β-casein to fold like the native protein
AU - Sood, Satish M.
AU - Erickson, Grant
AU - Jhawar, Harbor
AU - Slattery, Charles W.
N1 - Native human β-casein (CN) at all phosphorylation levels exhibits reproducible behavior and appears to have a unique, stable folding pattern. In contrast, the recombinant non-phosphorylated form of human β-CN (β-CN-0P) with the exact amino acid sequence (wild-type), expressed and purified from Escherichia coli, differs greatly in its behavior from the native protein and the complexes formed are unstable to thermal cycling.
PY - 2005/8
Y1 - 2005/8
N2 - Native human β-casein (CN) at all phosphorylation levels exhibits reproducible behavior and appears to have a unique, stable folding pattern. In contrast, the recombinant non-phosphorylated form of human β-CN (β-CN-0P) with the exact amino acid sequence (wild-type), expressed and purified from Escherichia coli, differs greatly in its behavior from the native protein and the complexes formed are unstable to thermal cycling. However, when it was incorporated into reconstituted milk micelles, using bovine κ-CN at a κ/β molar ratio of 1/3 with added Ca2+ ions and inorganic phosphate (Pi) at levels that would ordinarily precipitate, its association behavior vs. temperature as monitored by turbidity (OD 400 nm) approximated that of native β-CN-0P. This suggests that the milk micelle system, and particularly the colloidal calcium phosphate, may act as a 'molecular chaperon' to direct the folding of the molecule into the highly stable conformation found in the purified native human β-CN molecule.
AB - Native human β-casein (CN) at all phosphorylation levels exhibits reproducible behavior and appears to have a unique, stable folding pattern. In contrast, the recombinant non-phosphorylated form of human β-CN (β-CN-0P) with the exact amino acid sequence (wild-type), expressed and purified from Escherichia coli, differs greatly in its behavior from the native protein and the complexes formed are unstable to thermal cycling. However, when it was incorporated into reconstituted milk micelles, using bovine κ-CN at a κ/β molar ratio of 1/3 with added Ca2+ ions and inorganic phosphate (Pi) at levels that would ordinarily precipitate, its association behavior vs. temperature as monitored by turbidity (OD 400 nm) approximated that of native β-CN-0P. This suggests that the milk micelle system, and particularly the colloidal calcium phosphate, may act as a 'molecular chaperon' to direct the folding of the molecule into the highly stable conformation found in the purified native human β-CN molecule.
KW - Colloidal calcium phosphate
KW - Molecular chaperon
KW - Protein folding
KW - Recombinant human β-casein
KW - Reconstituted milk micelle formation
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U2 - 10.1007/s10930-005-7591-5
DO - 10.1007/s10930-005-7591-5
M3 - Article
C2 - 16323043
SN - 1572-3887
VL - 24
SP - 379
EP - 384
JO - Protein Journal
JF - Protein Journal
IS - 6
ER -