Abstract
| Originalsprog | Engelsk |
|---|---|
| Tidsskrift | Journal of Molecular Biology |
| Vol/bind | 318 |
| Udgave nummer | 3 |
| Sider (fra-til) | 805-14 |
| Antal sider | 9 |
| ISSN | 0022-2836 |
| DOI | |
| Status | Udgivet - 2002 |
Bibliografisk note
Keywords: Animals; Cattle; Circular Dichroism; Diazepam Binding Inhibitor; Drug Stability; Hydrogen-Ion Concentration; Nuclear Magnetic Resonance, Biomolecular; Protein Denaturation; Protein Folding; Recombinant Proteins; Spectrometry, FluorescenceAdgang til dokumentet
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Transient intermediary states with high and low folding probabilities in the apparent two-state folding equilibrium of ACBP at low pH. / Thomsen, Jens K; Kragelund, Birthe B; Teilum, Kaare; Knudsen, Jens; Poulsen, Flemming M.
I: Journal of Molecular Biology, Bind 318, Nr. 3, 2002, s. 805-14.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › peer review
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TY - JOUR
T1 - Transient intermediary states with high and low folding probabilities in the apparent two-state folding equilibrium of ACBP at low pH
AU - Thomsen, Jens K
AU - Kragelund, Birthe B
AU - Teilum, Kaare
AU - Knudsen, Jens
AU - Poulsen, Flemming M
N1 - Keywords: Animals; Cattle; Circular Dichroism; Diazepam Binding Inhibitor; Drug Stability; Hydrogen-Ion Concentration; Nuclear Magnetic Resonance, Biomolecular; Protein Denaturation; Protein Folding; Recombinant Proteins; Spectrometry, Fluorescence
PY - 2002
Y1 - 2002
N2 - Measurements of the stability as a function of pH for the acyl-coenzyme A binding protein (ACBP) has shown a significant difference in the pH transition midpoint measured by NMR spectroscopy at pH 3.12 and the transition midpoint measured at pH 2.92 and 2.97 by circular dichroism and by fluorescence spectroscopy, respectively. A similar behavior has not been observed in other proteins. It is suggested that these differences arise because the population of the unfolded molecules still contains significant amounts of native like secondary and tertiary structure. NMR spectroscopy measures the concentration of the two components of the folding unfolding equilibrium individually, whereas circular dichroism and fluorescence measure the concentration of the conformations of the light-absorbing chromophores present in both the folded and the unfolded molecules. In the narrow pH range, nascent structure can be detected as the average amount of secondary structure per unfolded molecule and hydrophobic interactions in the population of unfolded molecules. These structures are not observable immediately by NMR spectroscopy; however, a chemical shift analysis of the peptide backbone (13)C chemical shift indicates strongly the existence of short-lived and transient helical structures at pH 2.3. Magnetization transfer studies have been applied to study the equilibrium between folded and unfolded ACBP near the pH transition point measured by NMR. This study has shown that there are two categories of subpopulations in the population of unfolded ACBP. One for which magnetization can be transferred to the folded form during the folding process, and one for which transfer is not observed. The molecules of the latter population of unfolded protein apparently, do not fold within the time-frame of the magnetization transfer experiment. This result suggests the existence of a subpopulation of the acid-unfolded protein molecules with a high propensity for folding. It is suggested that in this subpopulation, a particular set of native like interactions in the peptide backbone and between side-chains in the peptide chain have to be formed.
AB - Measurements of the stability as a function of pH for the acyl-coenzyme A binding protein (ACBP) has shown a significant difference in the pH transition midpoint measured by NMR spectroscopy at pH 3.12 and the transition midpoint measured at pH 2.92 and 2.97 by circular dichroism and by fluorescence spectroscopy, respectively. A similar behavior has not been observed in other proteins. It is suggested that these differences arise because the population of the unfolded molecules still contains significant amounts of native like secondary and tertiary structure. NMR spectroscopy measures the concentration of the two components of the folding unfolding equilibrium individually, whereas circular dichroism and fluorescence measure the concentration of the conformations of the light-absorbing chromophores present in both the folded and the unfolded molecules. In the narrow pH range, nascent structure can be detected as the average amount of secondary structure per unfolded molecule and hydrophobic interactions in the population of unfolded molecules. These structures are not observable immediately by NMR spectroscopy; however, a chemical shift analysis of the peptide backbone (13)C chemical shift indicates strongly the existence of short-lived and transient helical structures at pH 2.3. Magnetization transfer studies have been applied to study the equilibrium between folded and unfolded ACBP near the pH transition point measured by NMR. This study has shown that there are two categories of subpopulations in the population of unfolded ACBP. One for which magnetization can be transferred to the folded form during the folding process, and one for which transfer is not observed. The molecules of the latter population of unfolded protein apparently, do not fold within the time-frame of the magnetization transfer experiment. This result suggests the existence of a subpopulation of the acid-unfolded protein molecules with a high propensity for folding. It is suggested that in this subpopulation, a particular set of native like interactions in the peptide backbone and between side-chains in the peptide chain have to be formed.
U2 - 10.1016/S0022-2836(02)00159-6
DO - 10.1016/S0022-2836(02)00159-6
M3 - Journal article
C2 - 12054824
VL - 318
SP - 805
EP - 814
JO - Journal of Molecular Biology
JF - Journal of Molecular Biology
SN - 0022-2836
IS - 3
ER -