Skip to main content
SpringerLink
Log in

POR hits the road: import and assembly of a plastid protein

  • Published:
Plant Molecular Biology Aims and scope Submit manuscript

Abstract

The biosynthesis of chlorophyll is a strictly light-dependent multistep process in higher plants. The light-dependent step is catalysed by NADPH:protochlorophyllide oxidoreductase (POR, EC.1.6.99.1), which reduces protochlorophyllide (Pchlide) to chlorophyllide (Chlide). POR is nucleus-encoded and post-translationally imported into plastids. It has been proposed that the import of a POR protein isozyme (PORA) is totally dependent on Pchlide and uses a novel import pathway. This proposal is based on findings that PORA import only occurs in the presence of Pchlide and that the presence of overexpressed precursor of Rubisco small subunit (pSS), a protein which is known to use the general import pathway, does not outcompete PORA import. Another study demonstrated that POR precursor protein (pPOR) can be cross-linked to one of the components in the translocation machinery, Toc75, in the absence of Pchlide, and that its import can be outcompeted by the addition of the pSS. This indicates that pSS and pPOR may use the same translocation mechanism. Thus, POR does not necessarily need Pchlide for import – which is in contrast to earlier observations – and the exact POR import mechanism remains unresolved. Once in the stroma, the POR transit peptide is cleaved off and the mature POR protein is associated to the plastid inner membranes. Formation of the correct membrane–associated, thermolysin-protected assembly is strictly dependent of NADPH. As a final step, the formation of the NADPH-Pchlide-POR complex occurs. When POR accumulates in the membranes of proplastids, an attraction of monogalactosyl diacylglycerol (MGDG) can occur, leading to the formation of prolamellar bodies (PLBs) and the development of etioplasts in darkness.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

References

  • Alefsen, H., Waegemann, K. and Soll, J. 1994. Analysis of the chloroplast protein import machinery. J. Plant Physiol. 144: 339–345.

    Google Scholar 

  • Armstrong, G.A., Runge, S., Frick, G., Sperling, U. and Apel, K. 1995. Identification of NADPH:protochlorophyllide oxidoreductase A and B: A branched pathway for light-dependent chlorophyll biosynthesis in Arabidopsis thaliana. Plant Phys. 108: 1505–1517.

    Google Scholar 

  • Aronsson, H. 2001. Plastid import and membrane association of NADPH:protochlorophyllide oxidoreductase (POR) – a key enzyme in chloroplast development. Ph D Dissertation. Göteborg University, Sweden. ISBN 91-88896-30-7

    Google Scholar 

  • Aronsson, H., Sohrt, K. and Soll, J. 2000. NADPH:protochlorophyllide oxidoreductase uses the general import pathway. Biol. Chem. 381: 1263–1267.

    Google Scholar 

  • Aronsson, H., Sundqvist, C., Timko, M.P. and Dahlin, C. 2001a. Characterisation of the assembly pathway of the pea NADPH:protochlorophyllide (Pchlide) oxidoreductase (POR), with emphasis on the role of its substrate, Pchlide. Physiol. Plant 111: 239–245.

    Google Scholar 

  • Aronsson, H., Sundqvist, C., Timko, M.P. and Dahlin, C. 2001b. The importance of the C-terminal region and Cys residues for the membrane association of the NADPH:protochlorophyllide oxidoreductase (POR) in pea (Pisum sativum). FEBS Lett. 502: 11–15.

    Google Scholar 

  • Batschauer, A., Santel, H.J. and Apel, K. 1982. The presence and synthesis of the NADPH-protochlorophyllide oxidoreductase in barley leaves with a high-temperature-induced deficiency of plastid ribosomes. Planta 154: 459–464.

    Google Scholar 

  • Bauer, J., Chen, K.H., Hiltbunner, A., Wehrli, E., Eugster, M., Schnell, D. and Kessler, F. 2000. The major protein import receptor of plastids is essential for chloroplast biogenesis. Nature 403: 203–207.

    Google Scholar 

  • Benli, M., Schulz, R. and Apel, K. 1991. Effect of light on NADPHprotochlorophyllide oxidoreductase of Arabidopsis thaliana. Plant Mol. Biol. 16: 615–625.

    Google Scholar 

  • Bölter, B., May, T. and Soll, J. 1998. A protein import receptor in pea chloroplasts, Toc86, is only a proteolytic fragment of a larger polypeptide. FEBS Lett. 441: 59–62.

    Google Scholar 

  • Dahlin, C., Sundqvist, C. and Timko, M.P. 1995. The in vitro assembly of the NADPHprotochlorophyllide oxidoreductase in pea chloroplasts. Plant Mol. Biol. 29: 317–330.

    Google Scholar 

  • Dahlin, C., Aronsson, H., Wilks, H., Lebedev, N., Sundqvist, C. and Timko, M.P. 1999. The importance of protein surface charge for catalytic activity and the interaction of NADPH:protochlorophyllide oxidoreductase (POR) with chloroplast membranes as revealed by alanine scanning mutagenesis. Plant Mol. Biol. 39: 309–323.

    Google Scholar 

  • Dahlin, C., Aronsson, H., Almkvist, J. and Sundqvist, C. 2000. Pchlide independent import of two NADPH:protochlorophyllide oxidoreductase proteins (PORA and PORB) from barley into isolated plastids. Physiol. Plant 109: 298–303.

    Google Scholar 

  • Eggink, L.L. and Hoober, J.K. 2000. Chlorophyll binding to peptide maquettes containing a retention motif. J. Biol. Chem. 275: 9087–9090.

    Google Scholar 

  • Engdahl, S., Aronsson, H., Sundqvist, C., Timko, M.P. and Dahlin, C. 2001. Association of the NADPH: protochlorophyllide oxidoreductase (POR) to isolated etioplast inner membranes from wheat. Plant J. 27: 297–304.

    Google Scholar 

  • Holtorf, H., Reinbothe, S., Reinbothe, C., Bereza, B. and Apel, K. 1995. Two routes of chlorophyllide synthesis that are differentially regulated by light in barley (Hordeum vulgare L.). Proc. Natl. Acad Sci. 92: 3254–3258.

    Google Scholar 

  • Jackson-Constan, D. and Keegstra, K. 2001. Arabidopsis genes encoding components of the chloroplastic protein import apparatus.Plant Physiol. 125: 1567–1576.

    Google Scholar 

  • Jarvis, P. and Soll, J. 2001. Toc, Tic, and chloroplast import.Biochim. Biophys. Acta 1541: 64–79.

    Google Scholar 

  • Jarvis, P., Chen, L-J., Li, H-m., Peto, C.A., Fankhauser, C. and Chory, J. 1998. An Arabidopsis mutant defective in the plastid general protein import apparatus. Science 282: 100–103.

    Google Scholar 

  • Klement, H., Helfrich, M., Oster, U., Schoch, S. and Rüdiger, W. 1999. Pigment-free NADPH:protochlorophyllide oxidoreductase from Avena sativa L. Eur. J. Biochem. 265: 862–874.

    Google Scholar 

  • Kovacheva, S., Ryberg, M. and Sundqvist, C. 2000. ADP/ATP and protein phosphorylation dependence of phototransformable protochlorophyllide in isolated etioplast membranes. Photosynth. Res. 64: 127–136.

    Google Scholar 

  • Lebedev, N., Karginova, O., McIvor, W. and Timko, M.P. 2001. Tyr275 and Lys279 stabilize NADPH within the catalytic site of NADPH:protochlorophyllide oxidoreductase and are involved in the formation of the enzyme photoactive state. Biochem. 40:12562–12574.

    Google Scholar 

  • Marrison, J.L., Schünmann, P.H.D., Ougham, H.J., Leech, R.M. 1996. Subcellular visualization of gene transcripts encoding key proteins of the chlorophyll accumulation process in developing chloroplasts. Plant Physiol. 110: 1089–1096.

    Google Scholar 

  • Oosawa, N., Masuda, T., Awai, K., Fusada, N., Shimada, H., Ohta, H. and Takamiya, K-H. 2000. Identification and light-induced expression of a novel gene of NADPH-protochlorophyllide oxidoreductase isoform in Arabidopsis thaliana. FEBS Lett 474: 133–136.

    Google Scholar 

  • Reinbothe, S., Runge, S., Reinbothe, C., van Cleve, B. and Apel, K. 1995a. Substrate-dependent transport of the NADPH:protochlorophyllide oxidoreductase into isolated plastids. Plant Cell 7: 161–172.

    Google Scholar 

  • Reinbothe, S., Reinbothe, C., Holtorf, H. and Apel, K. 1995b. Two NADPH:protochlorophyllide oxidoreductase in barley: evidence for the selective disappearance of PORA during the light-induced greening of etiolated seedlings. Plant Cell 7: 1933–1940.

    Google Scholar 

  • Reinbothe, S., Reinbothe, C., Neumann, D. and Apel, K. 1996. A plastid enzyme arrested in the step of precursor translocation in vivo. Proc. Natl. Acad Sci. 93: 12026–12030.

    Google Scholar 

  • Reinbothe, C., Lebedev, N., Apel, K. and Reinbothe, S. 1997. Regulation of chloroplast protein import through a protochlorophyllide-responsive transit peptide. Proc. Natl. Acad Sci. 94: 8890–8894.

    Google Scholar 

  • Reinbothe, S., Mache, R. and Reinbothe, C. 2000. A second, substrate-dependent site of protein import into chloroplasts. Proc. Natl. Acad Sci. 97: 9795–9800.

    Google Scholar 

  • Ryberg, M. and Dehesh, K. 1986. Localization of NADPHprotochlorophyllide oxidoreductase in dark-grown wheat (Triticum aestivum) by immuno-electron microscopy before and after transformation of the prolamellar bodies. Physiol. Plant 66: 616–624.

    Google Scholar 

  • Schulz, R., Steinmüller, K., Klaas, M., Forreiter, C., Rasmussen, S., Hiller, C. and Apel, K. 1989. Nucleotide sequence of a cDNA coding for the NADPH-protochlorophyllide oxidoreductase (PCR) of barley (Hordeum vulgare L.) and its expression in Escherichia coli. Mol. Gen. Genet. 217: 355–361.

    Google Scholar 

  • Selstam, E. and Widell-Wigge, A. 1989. Hydrophobicity of protochlorophyllide oxidoreductase, characterized by means of Triton X-114 partioning of isolated etioplast membrane fractions. Physiol. Plant 77: 401–406.

    Google Scholar 

  • Spano, A.J., He, Z., Michel, H., Hunt, D.F. and Timko, M.P. 1992. Molecular cloning, nuclear gene structure, and developmental expression of NADPH:protochlorophyllide oxidoreductase in pea (Pisum sativum L.) Plant Mol. Biol. 18: 967–972.

    Google Scholar 

  • Teakle, G.R. and Griffiths, W.T. 1993. Cloning characterization and import studies on protochlorophyllide reductase from wheat (Triticum aestivum). Biochem. J. 296: 225–230.

    Google Scholar 

  • Townley, H.E., Sessions, R.B., Clarke, A.R., Dafforn, T.R., Griffiths, W.T. 2001. Protochlorophyllide oxidoreductase: a homology model examined by site-directed mutagenesis. Proteins 44: 329–335.

    Google Scholar 

  • Wiktorsson, B., Ryberg, M. and Sundqvist, C. 1996. Aggregation of NADPH-protochlorophyllide oxidoreductase-pigment complexes is favoured by protein phosphorylation. Plant Physiol. Biochem. 34: 23–34.

    Google Scholar 

  • Yu, T-S., and Li, H-M. 2001. Chloroplast protein translocation components at Toc159 and at Toc33 are not essential for chloroplast biogenesis in guard cells and root cells. Plant Physiol. 127: 90–96.

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Department of Biology, Leicester University, University Rd, Leicester, LE1 7RH, United Kingdom

    Henrik Aronsson

  2. Department of Plant Physiology, Göteborg University, Box 461, SE-405 30, Göteborg, Sweden

    Christer Sundqvist

  3. School of Business and Engineering, Halmstad University, Box 823, SE-301 18, Halmstad, Sweden

    Clas Dahlin

Authors
  1. Henrik Aronsson
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Christer Sundqvist
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Clas Dahlin
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Henrik Aronsson.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Aronsson, H., Sundqvist, C. & Dahlin, C. POR hits the road: import and assembly of a plastid protein. Plant Mol Biol 51, 1–7 (2003). https://doi.org/10.1023/A:1020795415631

Download citation

  • Issue Date:

  • DOI: https://doi.org/10.1023/A:1020795415631

Search

Navigation