PMID- 17002304
OWN - NLM
STAT- MEDLINE
DCOM- 20061107
LR  - 20240312
IS  - 0006-2960 (Print)
IS  - 1520-4995 (Electronic)
IS  - 0006-2960 (Linking)
VI  - 45
IP  - 39
DP  - 2006 Oct 3
TI  - The free energy of dissociation of oligomeric structure in phycocyanin is not 
      linear with denaturant.
PG  - 12050-9
AB  - Using SEC HPLC and fluorescence anisotropy, absorption spectra were assigned to 
      the specific oligomeric structures found with phycocyanin. The absorption spectra 
      were used to quantify the population of each oligomeric form of the protein as a 
      function of both urea concentration and temperature. Phycocyanin hexamers 
      dissociate to trimers with equilibrium constants of 10(-6) to 10(-5). Phycocyanin 
      trimers dissociate to monomers with equilibrium constants of 10(-15) to 10(-12). 
      Both dissociation constants increase linearly with increasing urea concentration, 
      and deltaG(o) values calculated from the equilibrium constants fit best with an 
      exponential function. Our findings appear in contrast with the commonly used 
      linear extrapolation model, deltaG(urea)(o) = deltaG(water)(o) + A[denaturant], 
      in which a linear relationship exists between the free energy of protein 
      unfolding or loss of quaternary structure and the denaturant concentration. Our 
      data examines a smaller range of denaturant concentration than generally used, 
      which might partially explain the inconsistency.
FAU - Thoren, Katie L
AU  - Thoren KL
AD  - Department of Chemistry, Lafayette College, Easton, Pennsylvania 18042, USA.
FAU - Connell, Katelyn B
AU  - Connell KB
FAU - Robinson, Taylor E
AU  - Robinson TE
FAU - Shellhamer, David D
AU  - Shellhamer DD
FAU - Tammaro, Margaret S
AU  - Tammaro MS
FAU - Gindt, Yvonne M
AU  - Gindt YM
LA  - eng
GR  - R15 GM067614/GM/NIGMS NIH HHS/United States
GR  - R15 GM067614-01/GM/NIGMS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Biochemistry
JT  - Biochemistry
JID - 0370623
RN  - 0 (Bacterial Proteins)
RN  - 11016-15-2 (Phycocyanin)
RN  - 8W8T17847W (Urea)
SB  - IM
MH  - Bacterial Proteins/*chemistry
MH  - Phycocyanin/*chemistry
MH  - Protein Denaturation
MH  - Protein Structure, Tertiary
MH  - Spectrometry, Fluorescence/methods
MH  - Synechococcus/*chemistry
MH  - Thermodynamics
MH  - Urea/*chemistry
PMC - PMC2519023
MID - NIHMS61326
EDAT- 2006/09/28 09:00
MHDA- 2006/11/09 09:00
PMCR- 2008/08/22
CRDT- 2006/09/28 09:00
PHST- 2006/09/28 09:00 [pubmed]
PHST- 2006/11/09 09:00 [medline]
PHST- 2006/09/28 09:00 [entrez]
PHST- 2008/08/22 00:00 [pmc-release]
AID - 10.1021/bi061140+ [doi]
PST - ppublish
SO  - Biochemistry. 2006 Oct 3;45(39):12050-9. doi: 10.1021/bi061140+.