%0 Journal Article
%T Volume Change of the Random Coil to Folded Conformational Transition of <i>Thermomyces</i> <i>lanuginosus</i> Xylanase at 24&#176C and pH = 7.0 via Application of the Clausius-Clapeyron Equation
%A Heather N. H. Wilks
%A Tara M. Arrington
%A Billy Mark Britt
%J Journal of Biophysical Chemistry
%P 134-142
%@ 2153-0378
%D 2014
%I Scientific Research Publishing
%R 10.4236/jbpc.2014.54015
%X A partial phase diagram characterizing the conformational change that occurs in Thermomyces lanuginosus xylanase as it is slowly heated in 150 mM sodium phosphate (pH = 7.0) has been con-structed from slow-scan-rate differential scanning calorimetry measurements. The Clausius-Clapeyron equation was applied to determine an associated volume change of -205 Lˇ¤mol<sup>-1</sup> at 24ˇăC, the equilibrium transition temperature at 1.0 atm pressure. This value is in excellent agreement with that predicted using a previously published [1] empirical equation for calculating the hydro-dynamic radius if the transition is regarded as from a random coil to a functional, folded state and with the assumption that the hydrodynamic radius is a good approximation of the true random coil radius. The existence of a low-temperature random coil is confirmed by circular dichroism and dynamic light scattering measurements. Thus, at 24ˇăC and 1.0 atm pressure the enzyme appears to fold from a random coil to a functional, folded form as it is slowly heated.
%K Clausius-Clapeyron
%K Conformational Change
%K Slow-Scan-Rate Differential Scanning Calorimetry
%K &lt
%K i&gt
%K Thermomyces&lt
%K /i&gt
%K &lt
%K i&gt
%K lanuginosus&lt
%K /i&gt
%K Xylanase
%K Volume Change
%U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=51532