Plastidic proteins containing motifs of nuclear transcription factors

New insights into plastid nucleoid structure and functionality

“…Among these proteins are several low molecular weight proteins (10-20 kDa) detected by cross-reaction with antibodies directed toward the bacterial HU (Briat et al 1984). Such basic low molecular weight proteins of eukaryotic origin could have replaced the bacterial histonelike proteins as has been hypothesized earlier (Kodama 2007).…”

“…PD3 also has a Jumonji C (jmjC) domain at the C-terminus which was proposed to be involved in chromatin remodeling (Kodama 2007). Structural data suggest that these plastid DNA binding proteins have evolved from nuclear transcription factors containing AT-hook motifs (Kodama 2007). The localization of the PD1 and PD3 proteins to the plastid nucleoids was shown by immunological analysis with specific antibodies.…”

“…In addition to the two or five AT-hooks of PD1 and PD3, respectively, PD3 possesses eight CxxC motifs, which are presumed to be metal binding sites of the protein (Sato et al 1995). PD3 also has a Jumonji C (jmjC) domain at the C-terminus which was proposed to be involved in chromatin remodeling (Kodama 2007). Structural data suggest that these plastid DNA binding proteins have evolved from nuclear transcription factors containing AT-hook motifs (Kodama 2007).…”

“…Examples are PEND, CND41, PD1, PD3 (Kodama 2007) as well as Whirly1 (Krause et al 2005;Grabowski et al 2008) and the newly identified ptNAP SWIB-4 (Melonek et al 2012). It has been suggested that these proteins have changed their subcellular localization during evolution and became plastid or dually targeted proteins.…”

“…Several of the plastid DNA binding proteins that were experimentally identified possess motifs that are typically found in nuclear transcription factors (Kodama 2007). Examples are PEND, CND41, PD1, PD3 (Kodama 2007) as well as Whirly1 (Krause et al 2005;Grabowski et al 2008) and the newly identified ptNAP SWIB-4 (Melonek et al 2012).…”