The Transport of Proteins Into Chloroplasts

Schmidt, Gregory W.; Mishkind, Michael

doi:10.1146/annurev.bi.55.070186.004311

Cited by 278 publications

(170 citation statements)

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“…The 113-residue (or 121-residue) sequence preceding the amino terminus of the mature protein is different from that of a typical signal peptide in the residue composition and predicted hydrophobicity. Thus, this sequence appears to function as a transit peptide that is required for targeting and transport of proteins to different cellular compartments (Schmidt and Mishkind, 1986;von Heijne et al, 1991). No significant sequence similarity is found in the transit peptides of the precursors between soluble starch synthase and four other enzymes localizing in the amyloplast, including GBSS ( Fig.…”

Section: Resultsmentioning

confidence: 99%

“…5 and 6). The sequence of the transit peptide is rich in Ala, Leu, Pro, Arg, and hydroxylic amino acids as Thr and Ser, as in the case of transit peptides of other proteins transported into cellular organelles, including amyloplast (Schmidt and Mishkind, 1986;von Heijne et al, 1991). Comparison of the tra.nsit peptides among five enzymes from rice seeds, participating in starch synthesis, indicates a poor sequence similarity to each other (Fig.…”

Section: Discussionmentioning

confidence: 99%

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Identification, cDNA Cloning, and Gene Expression of Soluble Starch Synthase in Rice (Oryza sativa L.) Immature Seeds

et al. 1993

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Three forms of soluble starch synthase were resolved by anionexchange chromatography of soluble extracts from immature rice (Oryza safiva 1.) seeds, and each of these forms was further purified by affinity chromatography. The 55-, 57-, and 57-kD proteins in the three preparations were identified as candidates for soluble starch synthase by western blot analysis using an antiserum against rice granule-bound starch synthase. It is interesting that the aminoterminal amino acid sequence was identical among the three proteins, except that the 55-kD protein lacked eight amino acids at the amino terminus. Thus, these three proteins are products of the same gene. lhe cDNA clones coding for this protein have been isolated from an immature rice seed library in Agtll using synthetic oligonucleotides as probes. The deduced amino acid sequence of this protein contains a lysine-X-glycine-glycine consensus sequence for the ADP-glucose-binding site of starch and glycogen synthases. Therefore, we conclude that this protein corresponds to a form of soluble starch synthase in immature rice seeds. The precursor of the enzyme contains 626 amino acids, including a 113-residue transit peptide at the amino terminus. lhe mature form of soluble starch synthase shares a significant but low sequence identity with rice granule-bound starch synthase and Escherichia coli glycogen synthase. However, several regions, including the substrate-binding site, are highly conserved among these three enzymes. Blot hybridization analysis demonstrates that the gene encoding soluble starch synthase is a single-copy gene in the rice genome and is expressed in both leaves and immature seeds. These results suggest that soluble and granule-bound starch synthases play distinct roles in starch biosynthesis of plant.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Identification, cDNA Cloning, and Gene Expression of Soluble Starch Synthase in Rice (Oryza sativa L.) Immature Seeds

et al. 1993

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“…The large proportion of hydroxylated and charged amino acids provides the transit sequences with a hydrophilic trait which was suggested to be important for interaction of the pre-peptide with the chloroplast import receptor (Soil, 1995). Secondly, chloroplast targeting signals typically have a propensity to form an (z-helix at least along the most N-terminal amino acid residues (Schmidt and Mishkind, 1986). In accordance with that common feature of transit peptides, the very first amino acid residues of BAS1 have an (z-helical character.…”

Section: The N-terminal Extension Of Basl Encodes the Chloroplast Tarmentioning

confidence: 99%

The plant 2‐Cys peroxiredoxin BAS1 is a nuclear‐encoded chloroplast protein: its expressional regulation, phylogenetic origin, and implications for its specific physiological function in plants

Baier

Dietz²

1997

The Plant Journal

216

140

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“…Chloroplast-encoded polypeptides are synthesized at or near their functional locations on thylakoid-bound ribosomes (21). Conversely, nuclearly encoded polypeptides must be imported from their site of synthesis in the cytosol (29). The fact that thylakoids are spatially separated from the delimiting envelope membranes indicates that assembly of these polypeptides is a multistep process, involving interaction with three different membranes.…”

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confidence: 99%

Light-Harvesting Chlorophyll a/b Protein

Cline¹

1988

Plant Physiol.

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The apoprotein of the light-harvesting chlorophyll alb protein (LHCP) is a major integral thylakoid membrane protein that is normally complexed with chlorophyll and xanthophylls and serves as the antenna complex of photosystem IL LHCP is encoded in the nucleus and synthesized in the cytosol as a higher molecular weight precursor that is subsequently imported into chloroplasts and assembled into thylakoids. In a previous study it was established that the LHCP precursor can integrate into isolated thylakoid membranes. The present study demonstrates that under conditions designed to preserve thylakoid structure, the inserted LHCP precursor is processed to mature size, assembled into the LHC II chlorophyll-protein complex, and localized to the appressed thylakoid membranes. Under these conditions, light can partially replace exogenous ATP in the membrane integration process.Thylakoid membranes contain approximately 45 different polypeptides, most of which are organized into four distinct supramolecular complexes: PSI, PSII, Cyt b/f, and the ATP synthase (11,23). In most plant chloroplasts, these complexes are nonuniformly distributed into two different structural thylakoid domains, the appressed membranes and the nonappressed membranes. PSII complexes are located predominantly in the appressed membranes, PSI and ATP synthase are located exclusively in the nonappressed membranes, and the Cyt blf complex appears to be present in both domains (23).Biogenesis of thylakoid protein complexes is an intriguing but little understood process. Each complex contains nuclearly encoded as well as chloroplast-encoded polypeptides (11). Thus, complex formation involves coordinate assembly of polypeptides that derive from two different cellular compartments. Chloroplast-encoded polypeptides are synthesized at or near their functional locations on thylakoid-bound ribosomes (21). Conversely, nuclearly encoded polypeptides must be imported from their site of synthesis in the cytosol (29). The fact that thylakoids are spatially separated from the delimiting envelope membranes indicates that assembly of these polypeptides is a multistep process, involving interaction with three different membranes. The assembly pathway for cytosolically synthesized thylakoid proteins has not been definitively established. However, recent studies (9, 30) suggest that these proteins are translocated across the envelope into the aqueous stromal matrix, where they are assembled into thylakoids by a second protein translocation/integration process.

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The Transport of Proteins Into Chloroplasts

Cited by 278 publications

References 1 publication

Identification, cDNA Cloning, and Gene Expression of Soluble Starch Synthase in Rice (Oryza sativa L.) Immature Seeds

Identification, cDNA Cloning, and Gene Expression of Soluble Starch Synthase in Rice (Oryza sativa L.) Immature Seeds

The plant 2‐Cys peroxiredoxin BAS1 is a nuclear‐encoded chloroplast protein: its expressional regulation, phylogenetic origin, and implications for its specific physiological function in plants

Light-Harvesting Chlorophyll a/b Protein

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