2X9J

Structure of the Mutant D206N of Phycoerythrobilin Synthase PebS from the Cyanophage P-SSM2 in complex with bound substrate Biliverdin IXA

2X9J の概要

• エントリーDOI: 10.2210/pdb2x9j/pdb
• 関連するPDBエントリー: 2VCK 2VCL 2VGR 2X9I
• 分子名称: PHYCOERYTHROBILIN SYNTHASE, BILIVERDINE IX ALPHA (3 entities in total)
• 機能のキーワード: oxidoreductase
• 由来する生物種: PROCHLOROCOCCUS PHAGE P-SSM2
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 55749.00

構造登録者

Busch, A.W.U.,Frankenberg-Dinkel, N.,Hofmann, E. (登録日: 2010-03-21, 公開日: 2010-11-17, 最終更新日: 2023-12-20)

主引用文献

Busch, A.W.U.,Reijerse, E.J.,Lubitz, W.,Hofmann, E.,Frankenberg-Dinkel, N.
Radical Mechanism of Cyanophage Phycoerythrobilin Synthase (Pebs).
Biochem.J., 433:469-, 2011

PubMed Abstract: PEB (phycoerythrobilin) is a pink-coloured open-chain tetrapyrrole molecule found in the cyanobacterial light-harvesting phycobilisome. Within the phycobilisome, PEB is covalently bound via thioether bonds to conserved cysteine residues of the phycobiliprotein subunits. In cyanobacteria, biosynthesis of PEB proceeds via two subsequent two-electron reductions catalysed by the FDBRs (ferredoxin-dependent bilin reductases) PebA and PebB starting from the open-chain tetrapyrrole biliverdin IXα. A new member of the FDBR family has been identified in the genome of a marine cyanophage. In contrast with the cyanobacterial enzymes, PebS (PEB synthase) from cyanophages combines both two-electron reductions for PEB synthesis. In the present study we show that PebS acts via a substrate radical mechanism and that two conserved aspartate residues at position 105 and 206 are critical for stereospecific substrate protonation and conversion. On the basis of the crystal structures of both PebS mutants and presented biochemical and biophysical data, a mechanism for biliverdin IXα conversion to PEB is postulated and discussed with respect to other FDBR family members.

PubMed: 21050180
DOI: 10.1042/BJ20101642

実験手法

X-RAY DIFFRACTION (1.85 Å)