Plastid-encoded RNA polymerase (PEP)

Plastid-encoded RNA polymerase (PEP), often called chloroplast RNA polymerase, is a multi-subunit, bacterial-type RNA polymerase located in plant chloroplasts[1][2][5]. Its core subunits are encoded by the plastid genome and structurally resemble prokaryotic (eubacterial) RNA polymerases[1][3][5]. PEP is responsible for the bulk of chloroplast gene transcription, particularly genes essential for photosynthesis and chloroplast function[1][2][3][5]. The PEP complex associates with numerous plastid-associated proteins (PAPs), most of which are nuclear-encoded and contribute to the assembly, stability, DNA binding, and regulatory functions of the complex[1][3][5]. PEP activity is further regulated by nuclear-encoded sigma factors, environmental stimuli such as light, redox changes, and stress responses[2][4]. PEP’s proper function is critical for plant growth and development, making it essential for studies in plant biology and crop biotechnology, but it is not a direct human therapeutic target[1][3][5].

Other names

Chloroplast RNA polymerasePlastid RNA polymerasePEP (Plastid-encoded RNA polymerase)Chloroplast PEPPlastid transcription machinery

Not applicable for drugs (no approved drugs or small molecules acting specifically through this polymerase in current pharmacology). Mechanistically, PEP enables transcription of chloroplast genes by recognizing DNA promoters with the help of nuclear-encoded sigma factors and associated proteins[1][2][5].