Abstract
We have examined the assembly of the nuclear-encoded subunits of the oxygen-evolving complex (OEC) after their import into isolated intact chloroplasts. We showed that all three subunits examined (OE33, OE23, and OE17) partition between the thylakoid lumen and a site on the inner surface of the thylakoid membrane after import in a homologous system (e.g., pea or spinach subunits into pea or spinach chloroplasts, respectively). Although some interspecies protein import experiments resulted in OEC subunit binding, maize OE17 did not bind thylakoid membranes in chloroplasts isolated from peas. Newly imported OE33 and OE23 were washed from the membranes at the same concentrations of urea and NaCl as the native, indigenous proteins; this observation suggests that the former subunits are bound productively within the OEC. Inhibition of neither chloroplast protein synthesis nor light- or ATP-dependent energization of the thylakoid membrane significantly affected these assembly reactions, and we present evidence suggesting that incoming subunits actively displace those already bound to the thylakoid membrane. Transport of OE33 took place primarily in the stromal-exposed membranes and proceeded through a protease-sensitive, mature intermediate. Initial binding of OE33 to the thylakoid membrane occurred primarily in the stromal-exposed membranes, from where it migrated with measurable kinetics to the granal region. In contrast, OE23 assembly occurred in the granal membrane regions. This information is incorporated into a model of the stepwise assembly of oxygen-evolving photosystem II.
Full Text
The Full Text of this article is available as a PDF (3.3 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Biekmann S., Feierabend J. Synthesis and degradation of unassembled polypeptides of the coupling factor of photophosphorylation CF1 in 70S ribosome-deficient rye leaves. Eur J Biochem. 1985 Nov 4;152(3):529–535. doi: 10.1111/j.1432-1033.1985.tb09228.x. [DOI] [PubMed] [Google Scholar]
- Bruce B. D., Malkin R. Biosynthesis of the chloroplast cytochrome b6f complex: studies in a photosynthetic mutant of Lemna. Plant Cell. 1991 Feb;3(2):203–212. doi: 10.1105/tpc.3.2.203. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cline K., Ettinger W. F., Theg S. M. Protein-specific energy requirements for protein transport across or into thylakoid membranes. Two lumenal proteins are transported in the absence of ATP. J Biol Chem. 1992 Feb 5;267(4):2688–2696. [PubMed] [Google Scholar]
- Debus R. J. The manganese and calcium ions of photosynthetic oxygen evolution. Biochim Biophys Acta. 1992 Oct 16;1102(3):269–352. doi: 10.1016/0005-2728(92)90133-m. [DOI] [PubMed] [Google Scholar]
- Eaton-Rye J. J., Murata N. Evidence that the amino-terminus of the 33 kDa extrinsic protein is required for binding to the Photosystem II complex. Biochim Biophys Acta. 1989 Nov 23;977(2):219–226. doi: 10.1016/s0005-2728(89)80075-1. [DOI] [PubMed] [Google Scholar]
- Eisenberg-Domovich Y., Oelmüller R., Herrmann R. G., Ohad I. Role of the RCII-D1 protein in the reversible association of the oxygen-evolving complex proteins with the lumenal side of photosystem II. J Biol Chem. 1995 Dec 15;270(50):30181–30186. doi: 10.1074/jbc.270.50.30181. [DOI] [PubMed] [Google Scholar]
- Ettinger W. F., Theg S. M. Physiologically active chloroplasts contain pools of unassembled extrinsic proteins of the photosynthetic oxygen-evolving enzyme complex in the thylakoid lumen. J Cell Biol. 1991 Oct;115(2):321–328. doi: 10.1083/jcb.115.2.321. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hashimoto A., Yamamoto Y., Theg S. M. Unassembled subunits of the photosynthetic oxygen-evolving complex present in the thylakoid lumen are long-lived and assembly-competent. FEBS Lett. 1996 Aug 5;391(1-2):29–34. doi: 10.1016/0014-5793(96)00686-2. [DOI] [PubMed] [Google Scholar]
- Leheny E. A., Theg S. M. Apparent Inhibition of Chloroplast Protein Import by Cold Temperatures Is Due to Energetic Considerations Not Membrane Fluidity. Plant Cell. 1994 Mar;6(3):427–437. doi: 10.1105/tpc.6.3.427. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Leuschner C., Bricker T. M. Interaction of the 33 kDa extrinsic protein with photosystem II: rebinding of the 33 kDa extrinsic protein to photosystem II membranes which contain four, two, or zero manganese per photosystem II reaction center. Biochemistry. 1996 Apr 9;35(14):4551–4557. doi: 10.1021/bi9522615. [DOI] [PubMed] [Google Scholar]
- Luzikov V. N. Proteolytic control over topogenesis of membrane proteins. FEBS Lett. 1986 May 12;200(2):259–264. doi: 10.1016/0014-5793(86)81148-6. [DOI] [PubMed] [Google Scholar]
- Mayfield S. P., Bennoun P., Rochaix J. D. Expression of the nuclear encoded OEE1 protein is required for oxygen evolution and stability of photosystem II particles in Chlamydomonas reinhardtii. EMBO J. 1987 Feb;6(2):313–318. doi: 10.1002/j.1460-2075.1987.tb04756.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mayfield S. P., Rahire M., Frank G., Zuber H., Rochaix J. D. Expression of the nuclear gene encoding oxygen-evolving enhancer protein 2 is required for high levels of photosynthetic oxygen evolution in Chlamydomonas reinhardtii. Proc Natl Acad Sci U S A. 1987 Feb;84(3):749–753. doi: 10.1073/pnas.84.3.749. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Merchant S., Selman B. R. Synthesis and Turnover of the Chloroplast Coupling Factor 1 in Chlamydomonas reinhardi. Plant Physiol. 1984 Jul;75(3):781–787. doi: 10.1104/pp.75.3.781. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mullet J. E., Klein P. G., Klein R. R. Chlorophyll regulates accumulation of the plastid-encoded chlorophyll apoproteins CP43 and D1 by increasing apoprotein stability. Proc Natl Acad Sci U S A. 1990 Jun;87(11):4038–4042. doi: 10.1073/pnas.87.11.4038. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ort D. R., Izawa S. Studies on the Energy-coupling Sites of Photophosphorylation: V. Phosphorylation Efficiencies (P/e(2)) Associated with Aerobic Photooxidation of Artificial Electron Donors. Plant Physiol. 1974 Mar;53(3):370–376. doi: 10.1104/pp.53.3.370. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Robinson C., Klösgen R. B. Targeting of proteins into and across the thylakoid membrane--a multitude of mechanisms. Plant Mol Biol. 1994 Oct;26(1):15–24. doi: 10.1007/BF00039516. [DOI] [PubMed] [Google Scholar]
- Schleyer M., Neupert W. Transport of proteins into mitochondria: translocational intermediates spanning contact sites between outer and inner membranes. Cell. 1985 Nov;43(1):339–350. doi: 10.1016/0092-8674(85)90039-x. [DOI] [PubMed] [Google Scholar]
- Schmidt G. W., Mishkind M. L. Rapid degradation of unassembled ribulose 1,5-bisphosphate carboxylase small subunits in chloroplasts. Proc Natl Acad Sci U S A. 1983 May;80(9):2632–2636. doi: 10.1073/pnas.80.9.2632. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Takahashi Y., Goldschmidt-Clermont M., Soen S. Y., Franzén L. G., Rochaix J. D. Directed chloroplast transformation in Chlamydomonas reinhardtii: insertional inactivation of the psaC gene encoding the iron sulfur protein destabilizes photosystem I. EMBO J. 1991 Aug;10(8):2033–2040. doi: 10.1002/j.1460-2075.1991.tb07733.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Theg S. M., Bauerle C., Olsen L. J., Selman B. R., Keegstra K. Internal ATP is the only energy requirement for the translocation of precursor proteins across chloroplastic membranes. J Biol Chem. 1989 Apr 25;264(12):6730–6736. [PubMed] [Google Scholar]
- Theg S. M., Scott S. V. Protein import into chloroplasts. Trends Cell Biol. 1993 Jun;3(6):186–190. doi: 10.1016/0962-8924(93)90212-j. [DOI] [PubMed] [Google Scholar]
- Yalovsky S., Schuster G., Nechushtai R. The apoprotein precursor of the major light-harvesting complex of photosystem II (LHCIIb) is inserted primarily into stromal lamellae and subsequently migrates to the grana. Plant Mol Biol. 1990 May;14(5):753–764. doi: 10.1007/BF00016508. [DOI] [PubMed] [Google Scholar]
- van Wijk K. J., Andersson B., Aro E. M. Kinetic resolution of the incorporation of the D1 protein into photosystem II and localization of assembly intermediates in thylakoid membranes of spinach chloroplasts. J Biol Chem. 1996 Apr 19;271(16):9627–9636. doi: 10.1074/jbc.271.16.9627. [DOI] [PubMed] [Google Scholar]