Prevention p-elimination

I he yllde as a ligand is unique lor two reasons its electron-donor capacity reduces positive charge on the transition-metal atom and the onium group p to the metal atom prevents p elimination, which would generate coordination sites on the metal atom for ligand decomposition. 

Peptides that form a helices that associate as coiled coils, or as three- or four-helix tetrameric bundles or amphipathic helices that associate with lipid bilayers have been made. More difficult has been the design of proteins that form (3 sheets. Many efforts are being made to xmderstand protein stability " by systematic substitutions of one residue for another. Addition of new disulfide linkages at positions selected by study of three-dimensional structures sometimes stabilizes enzymes. On the other hand elimination of unnecessary cysteine residues can enhance stability by preventing p elimination and replacement of asparagine by threonine can improve the thermostability of enzymes by preventing deami-dation. ... 

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