TY - JOUR
T1 - A folding pattern that is stable to thermal cycling is achieved by long term storage of recombinant human β-casein with four extra N-terminals amino-acid residues at -20 °C
AU - Sood, Satish M.
AU - Booth, Cassie
AU - Jhawar, Harbir
AU - Slattery, Charles W.
N1 - Studies have followed the turbidity (OD400 nm) of beta-casein (CN) as temperature (T) increased from 4 to 37 degrees C. Native non-phosphorylated beta-CN showed a turbidity increase above 25 degrees C and precipitated at about 22 degrees C in 5mM Ca+2. These patterns were reproducible upon T-cycling ...
PY - 2006/10/1
Y1 - 2006/10/1
N2 - Studies have followed the turbidity (OD400 nm) of β-casein (CN) as temperature (T) increased from 4 to 37 °C. Native non-phosphorylated β-CN showed a turbidity increase above 25 °C and precipitated at about 22 °C in 5 mM Ca+2. These patterns were reproducible upon T-cycling while those of recombinant β-CN proteins are not. Here, a wild-type recombinant that was thermally stable after being frozen in solution and stored at -20 °C for a prolonged period of time was denatured with guanidine HCl and refolded by dialysis against buffer. This protein was again not stable to T-cycling. A recombinant mutant with four extra N-terminal amino acids was very stable to T-cycling, both with and without 5 mM Ca+2. However, it was still much different than the native protein. These results indicate that there are probably many energy minima for this protein and emphasize the possibility of "chaperon-like" conditions for proper folding of human β-CN.
AB - Studies have followed the turbidity (OD400 nm) of β-casein (CN) as temperature (T) increased from 4 to 37 °C. Native non-phosphorylated β-CN showed a turbidity increase above 25 °C and precipitated at about 22 °C in 5 mM Ca+2. These patterns were reproducible upon T-cycling while those of recombinant β-CN proteins are not. Here, a wild-type recombinant that was thermally stable after being frozen in solution and stored at -20 °C for a prolonged period of time was denatured with guanidine HCl and refolded by dialysis against buffer. This protein was again not stable to T-cycling. A recombinant mutant with four extra N-terminal amino acids was very stable to T-cycling, both with and without 5 mM Ca+2. However, it was still much different than the native protein. These results indicate that there are probably many energy minima for this protein and emphasize the possibility of "chaperon-like" conditions for proper folding of human β-CN.
KW - Chaperon-like conditions
KW - Protein folding
KW - Recombinant human β-caseins
KW - Thermal cycling
KW - Turbidity
UR - http://www.scopus.com/inward/record.url?scp=33748893947&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33748893947&partnerID=8YFLogxK
U2 - 10.1016/j.abb.2006.07.008
DO - 10.1016/j.abb.2006.07.008
M3 - Article
C2 - 16949550
SN - 0003-9861
VL - 454
SP - 55
EP - 58
JO - Archives of Biochemistry and Biophysics
JF - Archives of Biochemistry and Biophysics
IS - 1
ER -