The following is the abstract to an article by Joan Emma Shea et al published in journal of chemical physics volume 113 number 17, 1 nov 2000 "The amino acid sequence and the folding motif are essential in determining the protein folding mechanism. The interplay between energetic (sequence-dependent) and topological (motif dependent) frustrations is investigated for two model beta-barrel proteins of the same native fold but with different interaction Hamiltonians. The nature of the folding transition state ensemble for both models is probed. The extent of structure in the transition state is determined by performing point mutations and recording their effect on stability of the transition state through their phi values. The transition state shows more strctural heterogeneity for the more frustrated sequence, a reflection of the increased roughness of the funneled energy landscape which restricts the number of pathways to thenative state. The validity of the psi analysis approach was assessed to be critically dependent on the degree of frustration of the model. The interpretation of psi alues as a measure of the strcture of the transition state breaks down for sequences with higher levels of frustration (lower cooperativity) in which a Kramer's description of the folding reaction is no longer appropriate." *what on earch is meant by "frustrations"??? *what are beta barrel proteins? *what is meant by "probed" when it was aid "the nature of the folding transition state ensemble for both models is probed" ?? *what are point mutations? *what is meant by "the transition state shows more structural heterogeneity for the more frustrated sequence" ? *what is "Kramer's description"? I need to present this article on friday... i need help ASAP!! thnx!!