Toward a mechanism for biliprotein lyases: revisiting nucleophilic addition to phycocyanobilin.
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.
Tu
Jun-Ming
JM
State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, P.R. China.
Zhou
Ming
M
Haessner
Rainer
R
Plöscher
Matthias
M
Eichacker
Lutz
L
Scheer
Hugo
H
Zhao
Kai-Hong
KH