Stepwise protein folding at near amino acid resolution by hydrogen exchange and mass spectrometry

• DOI: 10.1073/pnas.1305887110
• Publication Date: 2013-04-20T03:34:59Z
• Authors: Wenbing Hu; Benjamin T. Walters; Zhong-Yuan Kan; Leland Mayne; Laura E. Rosen; Susan Marqusee; S. Walter Englander
• Keywords: Folding (DSP implementation); Cooperativity; Hydrogen–deuterium exchange; Equilibrium unfolding

The kinetic folding of ribonuclease H was studied by hydrogen exchange (HX) pulse labeling with analysis an advanced fragment separation mass spectrometry technology. results show that proceeds through distinct intermediates in a stepwise pathway sequentially incorporates cooperative native-like structural elements to build the native protein. Each step is seen as concerted transition one or more segments from HX-unprotected HX-protected state. Deconvolution data near amino acid resolution shows each corresponds secondary element protein, termed “foldon.” folded segment retained subsequent steps foldon addition, revealing buildup structure via single dominant pathway. Analysis pertinent literature suggests this model consistent experimental for many proteins and some current theoretical results. Two biophysical principles appear dictate behavior. principle cooperativity determines central role units. An interaction “sequential stabilization” based on interfoldon interactions orders