Identification and Characterization of Genes for Polypeptides of the Thylakoid Membrane

Restriction-site variation in chloroplast DNA was examined in the morphologically distinct and monotypic genus Heterogaura and the related speciose genus Clarkia (Onagraceae), both native to California. Of the 605 restriction sites surveyed, a total of 119 mutations were identified. Of these, 55 were shared by at least two species and were used to construct a most parsimonious phylogenetic tree. This analysis, as well as one based on a distance metric, provided evidence that Heterogaura and Clarkia dudleyana, a member of a phylogenetically advanced section, share a more recent common ancestor than either does with any other species. The two species are more closely related than nearly all pairs of Clarkia tested. The origin of Heterogaura from within another genus raises important questions about the adequacy of morphological data and suggests that the relationships of other wellknown monotypic plant genera should be reinvestigated.

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“…§1734 solely to indicate this fact. (18), also in Onagraceae. A total of 119 mutations were identified among the eight species of sect.…”

mentioning

confidence: 96%

Chloroplast DNA evidence for the origin of the genus Heterogaura from a species of Clarkia (Onagraceae)

Sytsma

Gottlieb

1986

Proc. Natl. Acad. Sci. U.S.A.

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“…Such studies have primarily focussed on few genes, like rbcL, psbA, atpB and atpE, which are transcribed monocistronically or bicistronically and exhibit relatively simple RNA patterns [4 -61. However, the genes for most, if not all, of the thylakoid polypeptides that have been located on higher plant plastid chromosomes are part of multicistronic transcription units [2,3] (Fig. 1) and generally give rise to complex RNA patterns that are indicative of extensive RNA processing.…”

mentioning

confidence: 99%

“…The majority of their approximately 50 constituent polypeptides is organized into four major functional complexes: the photosystems I and 11, the cytochrome h/f complex and the ATP synthase, which act cooperatively to convert light energy into high-energy chemical metabolites (reciewed in [l]). In eukaryotic plants these specialized biomembranes are genetic mosaics [2,31 and, consequently, their biogenesis requires the coordinated activities of nuclear and plastid genes. To understand the underlying integrative mechanisms it is imperative first to elucidate the expression of the component genomes.…”

mentioning

confidence: 99%

Complex RNA maturation in chloroplasts

Westhoff

Herrmann

1988

European Journal of Biochemistry

228

192

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ThepsbB operon of the spinach plastid chromosome encodes the genes for the 51-kDa chlorophyll a apoprotein (psbB), the 10-kDa phosphoprotein (psbH), both associated with photosystem 11, as well as cytochrome b6 (petB) and subunit IV (petD) of the cytochrome b/fcomplex in the order given. These genes are not expressed coordinately. The RNA pattern of this DNA region is complex and resolves into eighteen major RNA species. Using northern and S1 protection analysis we demonstrate (a) that all RNA species derive from one DNA strand and hybridize in an overlapping fashion; and (b) that they arise by processing rather than by multiple transcription initiation/ termination. (c) The operon is bordered by a single prokaryote-like promotor in front of psbB, and by a putative factor-independent terminator with characteristic sequence elements following petD. The terminator appears to function bidirectionally. (d) At least four distinct modification activities operate on the putative primary transcript of 5650 nucleotides and on the processing intermediates, including a novel endonucleolytic activity cleaving within a characteristic hexanucleotide motif, 3'-exonucleolytic activity at discrete RNA ends, 5' shortage of mRNA (psbB), and excision of class I1 intervening sequences (petB and petD). (e) Kinetically, maturation of the primary transcript is largely a stochastic process. (f) Processing results ultimately in the formation of monocistronic mRNAs for each of the two photosystem I1 polypeptides and a bicistronic mRNA encoding both subunits of the cytochrome blfcomplex. We postulate that these RNA species represent the translationally active components in the non-coordinate dark/light expression of these genes. (g) Light is without any noticeable effect on posttranscriptional modification. Under our conditions it appears to operate at a translational rather than a transcriptional or posttranscriptional level indicating that the biogenesis of thylakoid membranes is regulated at various levels.Thylakoid membranes are the principal energy-transducing structures in plants. The majority of their approximately 50 constituent polypeptides is organized into four major functional complexes: the photosystems I and 11, the cytochrome h/f complex and the ATP synthase, which act cooperatively to convert light energy into high-energy chemical metabolites (reciewed in [l]). In eukaryotic plants these specialized biomembranes are genetic mosaics [2, 31 and, consequently, their biogenesis requires the coordinated activities of nuclear and plastid genes. To understand the underlying integrative mechanisms it is imperative first to elucidate the expression of the component genomes.The expression of plastid genes is poorly understood. Only a few studies have directly examined the synthesis of RNA from polypeptide-encoding plastid genes at the molecular level. Such studies have primarily focussed on few genes, like rbcL, psbA, atpB and atpE, which are transcribed monocistronically or bicistronically and exhibit relatively simple RNA patterns ...

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“…Intact etioplasts were shown to effectively translate encoded Chl a-binding apoproteins, P700, CP47, CP43, D2 the chlorophyll apoproteins, to take up and esterify the and D1 (Chl aP) [8,9], nor nuclear-encoded Chl a/b-binding exogenously added substrates, chlorophyllide a and Zn-pheoapoproteins [10,11], although the plastid-encoded Chl aP are phorbidea, with geranylgeraniolpyrophosphate. For stabilization translated and degraded at high rates [12,13].…”

Section: Cp43 D2 and DI In Intact Etioplasts From Barley (Hordeummentioning

confidence: 99%

Stabilization of the chlorophyll binding apoproteins, P700, CP47, CP43, D2, and D1, by synthesis of Zn‐pheophytin a in intact etioplasts from barley

Eichacker¹,

Müller²,

Helfrich³

1996

FEBS Letters

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In isolated etioplasts, Chl formation is paralleled by accuAbstract Chlorophyll a was compared with Zn-pheophytin a for stabilization of chlorophyll binding apoproteins, P700, CP47, mulation of the plastid-encoded Chl-binding apoproteins [8]. CP43, D2, and DI, in intact etioplasts from barley (HordeumIn the absence of Chl, etioplasts accumulate neither plastidvulgare L.). Intact etioplasts were shown to effectively translate encoded Chl a-binding apoproteins, P700, CP47, CP43, D2 the chlorophyll apoproteins, to take up and esterify the and D1 (Chl aP) [8,9], nor nuclear-encoded Chl a/b-binding exogenously added substrates, chlorophyllide a and Zn-pheoapoproteins [10,11], although the plastid-encoded Chl aP are phorbidea, with geranylgeraniolpyrophosphate. For stabilization translated and degraded at high rates [12,13]. Via de novo of P700, CP47, D2, and D1, the product, Zn-pheophytin a, was synthesis of Chl from the precursors, Chlide and PhPP or shown to substitute for chlorophyll a. Stabilization of CP43 was GGPP, Chl aP were stabilized posttranslationally against proselectively increased in the presence of Zn-pheophytin a. The teolytic digestion and were shown to accumulate in the inner degree of stabilization was shown to depend on the amount of etioplast membranes during translation in a lysed etioplast newly synthesized Zn-pheophytin a and on the central atom of the chlorophyll molecule, expression system [14,15]. Here, we used Zn-pheophytin a (Zn-phe) as a tool, to show Key words." Chlorophyll; Reaction center protein;the impact of the central atom of Chl for stabilization of the Stabilization; Etioplast; Greening newly synthesized Chl aP. Materials and methods 1. Introduction Plant growth and plastid isolationBarley (Hordeum vulgare L., var. Steffi) seeds were planted in moistEtioplasts isolated from 4-day-old dark-grown barley are an vermiculite and grown for 4.25 days at 25°C in a light-tight growth ideal in vitro system to study the chlorophyll a (Chl)-dependchamber located in a dark room. At this stage of development, seedent accumulation of higher plant photosystems. In barley, lings were 4-5 cm tall and still within the coleoptile. Approximately 60 etioplasts are formed from proplastids in the absence of light g of etiolated primary leaves were cut 1 cm above the seed and were during the developmental phase of early primary leaf and ground in ice-cold buffer A (0.4 M Sorbit, 2 mM EDTA, 50 mM HEPES, pH 8.0) and cell organelles were concentrated by a brief plastid development [1]. centrifugation (4097xg, 3 min). Intact etioplasts were isolated by Etioplasts accumulate protochlorophyllide a (Pchlide), a Percoll step gradient centrifugation (35/65% Percoll, 0.4 M Sorbit, Chl precursor. In the light, Pchlide is reduced to chlorophyl-2 mM EDTA, 50 mM HEPES, pH 8.0; 4097Xg, 7.5 min). The Perlide a (Chlide) by protochlorophyllide oxidoreductase in a coll interface was aspirated, diluted 10-fold in buffer B (0.4 M Sorbit, 50 mM HEPES, pH 8.0) and intact etioplasts were repelleted NADPH-dependent reaction [2...

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Identification and Characterization of Genes for Polypeptides of the Thylakoid Membrane

Cited by 65 publications

References 16 publications

Chloroplast DNA evidence for the origin of the genus Heterogaura from a species of Clarkia (Onagraceae)

Chloroplast DNA evidence for the origin of the genus Heterogaura from a species of Clarkia (Onagraceae)

Complex RNA maturation in chloroplasts

Stabilization of the chlorophyll binding apoproteins, P700, CP47, CP43, D2, and D1, by synthesis of Zn‐pheophytin a in intact etioplasts from barley

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