Required for the activity of the plastid-encoded RNA polymerase (PEP) and full expression of genes transcribed by PEP (PubMed:24246379). Required for the proper build-up and formation of the PEP-complex (PubMed:25599833). Component of the plastid-encoded plastid RNA polymerase (PEP) complex. Pale yellow-green leaf phenotype. Reduced levels of plastid ribosomes and defects in plastid mRNA metabolism. Belongs to the MurCDEF family. MurE subfamily. Truncated N-terminus.