Structure of the multi-subunit chloroplast RNA polymerase

authored by

Paula F V do Prado, Frederik M Ahrens, Monique Liebers, Noah Ditz, Hans-Peter Braun, Thomas Pfannschmidt, Hauke Hillen

Abstract

Chloroplasts contain a dedicated genome that encodes subunits of the photosynthesis machinery. Transcription of photosynthesis genes is predominantly carried out by a plastid-encoded RNA polymerase (PEP), a nearly 1 MDa complex composed of core subunits with homology to eubacterial RNA polymerases (RNAPs) and at least 12 additional chloroplast-specific PEP-associated proteins (PAPs). However, the architecture of this complex and the functions of the PAPs remain unknown. Here, we report the cryo-EM structure of a 19-subunit PEP complex from Sinapis alba (white mustard). The structure reveals that the PEP core resembles prokaryotic and nuclear RNAPs but contains chloroplast-specific features that mediate interactions with the PAPs. The PAPs are unrelated to known transcription factors and arrange around the core in a unique fashion. Their structures suggest potential functions during transcription in the chemical environment of chloroplasts. These results reveal structural insights into chloroplast transcription and provide a framework for understanding photosynthesis gene expression.

Organisation(s)

Institute of Botany
Section Plant Physiology
Institute of Plant Genetics
Section Plant Molecular Biology and Plant Proteomics

External Organisation(s)

University of Göttingen
Universitätsmedizin Göttingen (UMG)

Type

Article

Journal

Molecular cell

Volume

84

Pages

910-925.e5

ISSN

1097-2765

Publication date

07.03.2024

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Molecular Biology, Cell Biology

Electronic version(s)

https://doi.org/10.1016/j.molcel.2024.02.003 (Access: Open)