Novel activity of a phycobiliprotein lyase: both the attachment of phycocyanobilin and the isomerization to phycoviolobilin are catalyzed by the proteins PecE and PecF encoded by the phycoerythrocyanin operon

FEBS Letters

Deng, Ming-Gang²  Meyer, Michaela¹  Scheer, Hugo¹  Strohmann, Brigitte¹  Storf, Max¹  Zhou, Ming²  Parbel, Axel¹  Zhao, Kai-Hong²  Zheng, Min² 

[1] Botanisches Institut, Universität München, Menzinger Str. 67, D-80638 Munich, Germany;College of Life Sciences, Wuhan University, Wuhan 430072, PR China

关键词: Phycobiliprotein;    Photosynthesis;    Phytochrome;    Chromophore;    Thiol addition;    Double bond shift;    Isomerization;    Cyanobacterium;    Phycobilin lyase;    MBV;    mesobiliverdin;    PCB;    phycocyanobilin;    PEB;    phycoerythrobilin;    PΦB;    phytochromobilin;    α-PEC;    phycoerythrocyanin α-subunit;    PecA;    apoprotein of phycoerythrocyanin α-subunit;    PecE and PecF;    components of α-PEC-phycoviolobilin lyase;    PVB;    phycoviolobilin (there are two terms for this chromophore in the literature: phycobiliviolin and phycoviolobilin. The latter is used because it is analogous to the names of the major phycobilins;    phycocyanobilin and phycoerythrobilin);   

DOI  :  10.1016/S0014-5793(00)01245-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The structure of phycoviolobilin, the photoactive chromophore of α-phycoerythrocyanin, is incompatible with a chromophore ligation to the apoprotein via SH-addition (cysteine) to a Δ3,3¹-double bond of the phycobilin. The two putative phycoerythrocyanin lyase genes of Mastigocladus laminosus, pecE and pecF, were overexpressed in Escherichia coli. Their action has been studied on the addition reaction of phycocyanobilin to apo-α-phycoerythrocyanin (PecA). In the absence of the components of α-PEC-phycoviolobilin lyase PecE and PecF, or in the presence of only one of them, phycocyanobilin binds covalently to PecA forming a fluorescent chromoprotein with a red-shifted absorption (λ _max=641 nm) and low photoactivity (<10%). In the presence of both PecE and PecF, a chromoprotein forms which by its absorption (λ _max=565 nm) and high photoreversible photochromism (100% type I) has been identified as integral α-phycoerythrocyanin. We conclude that PecE and PecF jointly catalyze not only the addition of phycocyanobilin to PecA, but also its isomerization to the native phycoviolobilin chromophore.

【 授权许可】

Unknown