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Pressure perturbation calorimetry of helical peptides
Author(s) -
Barrett Devin G.,
Minder C. Michael,
Mian Michelle U.,
Whittington Shelly J.,
Cooper W. John,
Fuchs Kristin M.,
Tripathy Ashutosh,
Waters Marcey L.,
Creamer Trevor P.,
Pielak Gary J.
Publication year - 2005
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.20819
Subject(s) - calorimetry , perturbation (astronomy) , chemistry , materials science , thermodynamics , physics , crystallography , quantum mechanics
Pressure perturbation calorimetry quantifies the temperature dependence of a solute's thermal expansion coefficient, providing information about solute–solvent interactions. We tested the idea that pressure perturbation calorimetry can provide information about solvent‐accessible surface area by studying peptides with different secondary structures. The peptides comprised two host–guest series: one predominately an α‐helix, the other predominately a polyproline II helix. In aqueous buffer, we find a correlation between the amount of secondary structure as assessed by circular dichroism spectropolarimetry and the pressure perturbation calorimetry data. We conclude that pressure perturbation calorimetry can provide information about the exposure of polar and nonpolar surface area. Data acquired in a buffered urea solution, however, are not as easily interpreted. Proteins 2006. © 2005 Wiley‐Liss, Inc.