We apply a simulational proxy of the -value analysis and perform extensive mutagenesis experiments to identify the nucleating residues in the folding “reactions” of two small lattice G polymers with different native geometries. Our findings show that for the more complex native fold (i.e., the one that is rich in nonlocal, long-range bonds), mutation of the residues that form the folding nucleus leads to a considerably larger increase in the folding time than the corresponding mutati...