Consequences of impaired 1-MDa TIC complex assembly for the abundance and composition of chloroplast high-molecular mass protein complexes.

Autor: Peter Schäfer, Stefan Helm, Daniel Köhler, Birgit Agne, Sacha Baginsky
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: PLoS ONE, Vol 14, Iss 3, p e0213364 (2019)
Druh dokumentu: article
ISSN: 1932-6203
DOI: 10.1371/journal.pone.0213364
Popis: We report a systematic analysis of chloroplast high-molecular mass protein complexes using a combination of native gel electrophoresis and absolute protein quantification by MSE. With this experimental setup, we characterized the effect of the tic56-3 mutation in the 1-MDa inner envelope translocase (TIC) on the assembly of the chloroplast proteome. We show that the tic56-3 mutation results in a reduction of the 1-MDa TIC complex to approximately 10% of wildtype levels. Hierarchical clustering confirmed the association of malate dehydrogenase (MDH) with an envelope-associated FtsH/FtsHi complex and suggested the association of a glycine-rich protein with the 1-MDa TIC complex. Depletion of this complex leads to a reduction of chloroplast ATPase to approx. 75% of wildtype levels, while the abundance of the FtsH/FtsHi complex is increased to approx. 140% of wildtype. The accumulation of the major photosynthetic complexes is not affected by the mutation, suggesting that tic56-3 plants can sustain a functional photosynthetic machinery despite a significant reduction of the 1-MDa TIC complex. Together our analysis expands recent efforts to catalogue the native molecular masses of chloroplast proteins and provides information on the consequences of impaired accumulation of the 1-MDa TIC translocase for chloroplast proteome assembly.
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