Abstract
We have recently discovered a protochlorophyllide (Pchlide)-based light-harvesting complex involved in chlorophyll a biosynthesis. This complex consists of the two previously identified NADPH:protochlorophyllide oxidoreductases (PORs), PORA and PORB, their natural substrates (Pchlide b and Pchlide a, respectively), plus NADPH. These are all held together in a stoichiometry of five PORA-Pchlide b-NADPH complexes and one PORB-Pchlide a-NADPH complex in the prolamellar body of etioplasts. The assembly of this novel light-harvesting POR-Pchlide complex (LHPP) requires both the proper interaction of the PORA and PORB with their cognate substrates as well as the oligomerization of the resulting POR-pigment-NADPH ternary complexes into the native, lipid-containing structure of the etioplast. In this study, we demonstrate that the conserved extra sequence that distinguishes PORA and PORB from the structurally related short-chain alcohol dehydrogenases, is dispensable for pigment binding but needed for the assembly of LHPP. As shown by in vitro mutagenesis, deleting this extra sequence gave rise to assembly-incompetent but pigment-containing PORA and PORB polypeptides.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
