Site-Specific Binding of Quinones to Proteins through Thiol Addition and Addition-Elimination Reactions

摘要

Enzymes and biological complexes often utilize noncovalently or covalently bound cofactors for their functions.Quinones are such molecules.Three classes of p-quinone:ubi-,mena-,and plastoqui-none are noncovalently bound components in photosynthetic electron transfer (ET) and respiratory chains.Nature has also crafted a variety of covalently bound quinone cofactors including a recently found cysteine tryptophylquinone (CTQ).CTQ consists of an o-quinone-modified tryptophan side chain cross-linked to a cysteine via a thioether bond.These natural constructs are in favor of generating new functions through chemical modification of proteins with quinones.