TY - JOUR

T1 - Structure of the multi-subunit chloroplast RNA polymerase

AU - do Prado, Paula F V

AU - Ahrens, Frederik M

AU - Liebers, Monique

AU - Ditz, Noah

AU - Braun, Hans-Peter

AU - Pfannschmidt, Thomas

AU - Hillen, Hauke

N1 - We thank Christian Dienemann and Ulrich Steuerwald (MPI-NAT cryo-EM facility) for technical assistance. This work was funded by the Deutsche Forschungsgemeinschaft under Germany's Excellence Strategy EXC 2067/1-390729940 (H.S.H.), Hertha Sponer College (P.F.V.d.P.), FOR2848 (P10, H.S.H.), SFB1565 (project number 469281184, P13, H.S.H.), PF323-7 (T.P.), the framework of the Priority Programme "MAdLand - Molecular Adaption to Land: Plant Evolution to Change (SPP2237, T.P.), PF323-9 (T.P.), and by the European Union (ERC Starting Grant MitoRNA, grant agreement no. 101116869, to H.S.H.). Views and opinions expressed are those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Council Executive Agency. Neither the European Union nor the granting authority can be held responsible for them.

PY - 2024/3/7

Y1 - 2024/3/7

N2 - 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.

AB - 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.

KW - chloroplast

KW - cryo-EM

KW - gene expression

KW - organelle

KW - photosynthesis

KW - plastid

KW - RNA

KW - RNA polymerase

KW - structural biology

KW - transcription

UR - http://www.scopus.com/inward/record.url?scp=85186639525&partnerID=8YFLogxK

U2 - 10.1016/j.molcel.2024.02.003

DO - 10.1016/j.molcel.2024.02.003

M3 - Article

C2 - 38428434

VL - 84

SP - 910-925.e5

JO - Molecular cell

JF - Molecular cell

SN - 1097-2765

IS - 5

ER -