title: Toward a mechanism for biliprotein lyases: revisiting nucleophilic addition to phycocyanobilin.
abstract: Biliprotein lyases attach linear-tetrapyrrolic bilins covalently to apoproteins, which is a prerequisite for the assembly of phycobiliproteins into phycobilisomes, the light-harvesting complexes of cyanobacteria. On the basis of the addition of thiol and imidazole to phycocyanobilin, we propose a generalized lyase reaction mechanism. The adducts contain isomerized phycocyanobilin that can be transferred by the lyase to apoproteins by either back-isomerization, generating phycocyanobilin-containing proteins, or direct transfer, generating phycoviolobilin-containing proteins.
authors.affiliation: State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, P.R. China.
authors.forename: Jun-Ming
authors.initials: JM
authors.lastname: Tu
authors.forename: Ming
authors.initials: M
authors.lastname: Zhou
authors.forename: Rainer
authors.initials: R
authors.lastname: Haessner
authors.forename: Matthias
authors.initials: M
authors.lastname: Plöscher
authors.forename: Lutz
authors.initials: L
authors.lastname: Eichacker
authors.forename: Hugo
authors.initials: H
authors.lastname: Scheer
authors.forename: Kai-Hong
authors.initials: KH
authors.lastname: Zhao