Structural and Biochemical Characterization of the Bilin Lyase CpcS from Thermosynechococcus elongatus

详细信息    查看全文

• 作者：Christina M. Kronfel ; Alexandre P. Kuzin ; Farhad Forouhar ; Avijit Biswas ; Min Su ; Scott Lew ; Jayaraman Seetharaman ; Rong Xiao ; John K. Everett ; Li-Chung Ma ; Thomas B. Acton ; Gaetano T. Montelione ; John F. Hunt ; Corry E. C. Paul ; Tierna M. Dragomani ; M. Nazim Boutaghou ; Richard B. Cole ; Christian Riml ; Richard M. Alvey ; Donald A. Bryant ; Wendy M. Schluchter
• 刊名：Biochemistry
• 出版年：2013
• 出版时间：December 3, 2013
• 年：2013
• 卷：52
• 期：48
• 页码：8663-8676
• 全文大小：606K
• 年卷期：v.52,no.48(December 3, 2013)
• ISSN：1520-4995

文摘

Cyanobacterial phycobiliproteins have evolved to capture light energy over most of the visible spectrum due to their bilin chromophores, which are linear tetrapyrroles that have been covalently attached by enzymes called bilin lyases. We report here the crystal structure of a bilin lyase of the CpcS family from Thermosynechococcus elongatus (TeCpcS-III). TeCpcS-III is a 10-stranded 尾 barrel with two alpha helices and belongs to the lipocalin structural family. TeCpcS-III catalyzes both cognate as well as noncognate bilin attachment to a variety of phycobiliprotein subunits. TeCpcS-III ligates phycocyanobilin, phycoerythrobilin, and phytochromobilin to the alpha and beta subunits of allophycocyanin and to the beta subunit of phycocyanin at the Cys82-equivalent position in all cases. The active form of TeCpcS-III is a dimer, which is consistent with the structure observed in the crystal. With the use of the UnaG protein and its association with bilirubin as a guide, a model for the association between the native substrate, phycocyanobilin, and TeCpcS was produced.