TY - JOUR
T1 - Polyproline II propensities from GGXGG peptides reveal an anticorrelation with β-sheet scales
AU - Shi, Zhengshuang
AU - Chen, Kang
AU - Liu, Zhigang
AU - Ng, Angela
AU - Bracken, W. Clay
AU - Kallenbach, Neville R.
PY - 2005/12/13
Y1 - 2005/12/13
N2 - There is growing appreciation of the functional relevance of unfolded proteins in biology. However, unfolded states of proteins have proven inaccessible to the usual techniques for high-resolution structural and energetic characterization. Unfolded states are still generally conceived of as statistical coils, based on the pioneering work of Flory [(1969) Statistical Mechanics of Chain Molecules (Wiley, New York)] and Tanford [(1968) Adv. Protein Chem. 23, 121-282]. Recently, several lines of independent evidence have raised doubts about the random coil model and offer support for alternative views. Here, we show that polyproline II conformation is dominant in a host-guest peptide model AcGGXGGNH2 (X ≠ glycine), in equilibrium predominantly with β-structure. This result is inconsistent with a random coil model and the general view that these peptides are unstructured. By calculating a set of apparent ΔG values from the measured coupling constants of the backbone amides, we can construct a polyproline II scale that correlates negatively with β-sheet scales.
AB - There is growing appreciation of the functional relevance of unfolded proteins in biology. However, unfolded states of proteins have proven inaccessible to the usual techniques for high-resolution structural and energetic characterization. Unfolded states are still generally conceived of as statistical coils, based on the pioneering work of Flory [(1969) Statistical Mechanics of Chain Molecules (Wiley, New York)] and Tanford [(1968) Adv. Protein Chem. 23, 121-282]. Recently, several lines of independent evidence have raised doubts about the random coil model and offer support for alternative views. Here, we show that polyproline II conformation is dominant in a host-guest peptide model AcGGXGGNH2 (X ≠ glycine), in equilibrium predominantly with β-structure. This result is inconsistent with a random coil model and the general view that these peptides are unstructured. By calculating a set of apparent ΔG values from the measured coupling constants of the backbone amides, we can construct a polyproline II scale that correlates negatively with β-sheet scales.
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U2 - 10.1073/pnas.0507124102
DO - 10.1073/pnas.0507124102
M3 - Article
C2 - 16330763
AN - SCOPUS:29144433298
SN - 0027-8424
VL - 102
SP - 17964
EP - 17968
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 50
ER -