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CpeS Is a Lyase Specific for Attachment of 3Z-PEB to Cys82 of β-phycoerythrin from Prochlorococcus marinus MED4
- Source :
- Journal of Biological Chemistry. 285:37561-37569
- Publication Year :
- 2010
- Publisher :
- Elsevier BV, 2010.
-
Abstract
- In contrast to the majority of cyanobacteria, the unicellular marine cyanobacterium Prochlorococcus marinus MED4 uses an intrinsic divinyl-chlorophyll-dependent light-harvesting system for photosynthesis. Despite the absence of phycobilisomes, this high-light adapted strain possesses β-phycoerythrin (CpeB), an S-type lyase (CpeS), and enzymes for the biosynthesis of phycoerythrobilin (PEB) and phycocyanobilin. Of all linear tetrapyrroles synthesized by Prochlorococcus including their 3Z- and 3E-isomers, CpeS binds both isomers of PEB and its biosynthetic precursor 15,16-dihydrobiliverdin (DHBV). However, dimerization of CpeS is independent of bilins, which are tightly bound in a complex at a ratio of 1:1. Although bilin binding by CpeS is fast, transfer to CpeB is rather slow. CpeS is able to attach 3E-PEB and 3Z-PEB to dimeric CpeB but not DHBV. CpeS transfer of 3Z-PEB exclusively yields correctly bound βCys(82)-PEB, whereas βCys(82)-DHBV is a side product of 3E-PEB transfer. Spontaneous 3E- and 3Z-PEB addition to CpeB is faulty, and products are in both cases βCys(82)-DHBV and likely a PEB bound at βCys(82) in a non-native configuration. Our data indicate that CpeS is specific for 3Z-PEB transfer to βCys(82) of phycoerythrin and essential for the correct configuration of the attachment product.
- Subjects :
- Amino Acid Motifs
Lyases
Phycoerythrobilin
Biochemistry
CPEB
chemistry.chemical_compound
Bacterial Proteins
Isomerism
Phycocyanobilin
Phycobilins
Bilin
Molecular Biology
Prochlorococcus
biology
Phycoerythrin
Cell Biology
biology.organism_classification
Lyase
Tetrapyrrole
chemistry
Enzymology
biology.protein
Phycobilisome
Protein Binding
Subjects
Details
- ISSN :
- 00219258
- Volume :
- 285
- Database :
- OpenAIRE
- Journal :
- Journal of Biological Chemistry
- Accession number :
- edsair.doi.dedup.....b155c459b85fe853cb8cc3de2a6f9bb7