Denaturant-gradient gel electrophoresis: technical aspects and practical applications

In denaturant-gradient gel electrophoresis (DGGE) proteins are run across a varying urea concentration in order to investigate their unfolding/refolding behavior in the presence of a chaotropic agent. The main parameter to characterize such denaturation curves is C(m), the urea concentration at one-half transition from the fast mobility of the folded, compact structure to the slow mobility of the unfolded molecule, with its much larger hydrodynamic volume. Comparison of C(m) ranks proteins on the score of their structural stability. Likewise, the free energy of the transition and its cooperativity, the reversibility of the process and the presence of intermediate conformations may be evaluated from the parameters of the curve.In this compilation, the current applications of the technique are reviewed, and some guidelines are given for the selection of the experimental conditions and for the interpretation of the results. Copyright (C) 1998 Elsevier Science B.V.