Analysis of oligomeric protein complexes in the chloroplast sub-proteome of nucleic acid-binding proteins from mustard reveals potential redox regulators of plastid gene expression

作者：Schroeter Yvonne; Steiner Sebastian; Matthaei Kevin; Pfannschmidt Thomas^*

来源：Proteomics, 2010, 10(11): 2191-2204.

DOI：10.1002/pmic.200900678

• 2-D blue native PAGE
• Chloroplast
• Nucleic acid-binding proteins
• Plant proteomics
• Redox regulation
• Sinapis alba

Photosynthetic light quality acclimation in plants involves redox-controlled changes in plastid gene expression. To study proteins potentially involved in this regulation, we isolated low-abundant chloroplast nucleic acid-binding proteins from the crucifere mustard (Sinapis alba) and investigated if photosynthetic redox signals affect their composition and/or oligomeric structure. We purified chloroplasts from plants subjected to light quality shifts and applied organelle lysates to heparin-Sepharose chromatography followed by 2-D blue native PAGE. We studied accumulation and structure of oligomeric protein complexes and applied MS/MS to identify them. We found ten oligomeric protein complexes of higher order and eleven smaller protein complexes or spots including plastid-encoded RNA polymerase (PEP), plastid transcriptionally active chromosome proteins, RNA-binding proteins, ribosomal subunits and chaperones. A translation elongation factor was found to be the only protein displaying major differences in its amounts in response to the growth lights. Furthermore, we found a novel thioredoxin as a subunit of the PEP, a 2-Cys-peroxiredoxin complex and a (soluble) ferredoxin:NADP-oxido-reductase, which represent potential redox regulator of plastid gene expression. A T-DNA knock-out line of the thioredoxin from Arabidopsis exhibits a yellowish-pale phenotype, demonstrating that this novel PEP subunit is essential for proper plastid development.

• 出版日期2010-6