Cleavage of the precursor of pea chloroplast cytochrome ƒ by leader peptidase from <i>Escherichia coli</i>

Anderson, Clare M.; Gray, John C.

doi:10.1016/0014-5793(91)80337-3

Cited by 33 publications

(11 citation statements)

References 27 publications

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“…Again, this appears very likely since the ApH-driven translocase has not been identified in cyanobacteria and only one of the proteins (CtpA) contains a twin-Arg motif known to be essential for targeting by this system in chloroplasts. We have omitted cytochrome f from this analysis because, although this protein is synthesised with an apparent signal peptide in chloroplasts (Anderson and Gray, 1991), the targeting pathway has yet to be elucidated. Cytochrome f is an integral membrane protein and may thus use the SRP pathway identified for the targeting of the light-harvesting chloroplast protein (LHCP), the best-studied thylakoid membrane protein (Li et al, 1995).…”

Section: Resultsmentioning

confidence: 99%

Unusual Characteristics of Amino‐Terminal and Hydrophobic Domains in Nuclear‐Encoded Thylakoid Signal Peptides

Brink¹,

Bogsch²,

Mant³

et al. 1997

European Journal of Biochemistry

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Thylakoid transfer signals carry information specifying translocation by either a Sec-or ApH-dependent protein translocator in the chloroplast thylakoid membrane, yet all resemble classical signal peptides in overall structural terms. Comparison of known transfer signals reveals two differences: (a) signals for the ApH-driven system invariably contain a critical twin-arginine (Arg-Arg) motif prior to the hydrophobic (H) domain, whereas known Sec-dependent signals contain lysine, and (b) the H-domains of Secdependent signals are generally longer. Previous work has shown that a twin-Arg motif before the Hdomain is critical for targeting by the ApH-dependent pathway; in this report we show that the charge characteristics of this region are not important for sorting by the Sec pathway. Twin-Lys, twin-Arg or single Arg are all acceptable to the Sec system, although single Lys/Arg is preferred. The single Lys in pre-plastocyanin can even be replaced by an uncharged residue without apparent effect. We have also generated a pre-plastocyanin mutant containing an H-domain which, in terms of hydropathy profile, is identical to that of a dpH-dependent protein. This mutant is also transported efficiently by the Sec system, demonstrating that hydrophobicity per se is not a key sorting determinant. However, the characteristics of the H-domain may be important in avoiding a different form of mis-targeting: to the endoplasmic reticulum. Thylakoid signal peptides have undergone substantial structural changes during the evolution of the chloroplast from endosymbiotic cyanobacterium: plastid-encoded and cyanobacterial signals contain H-domains that are highly hydrophobic and enriched in Leu and aromatic residues, whereas nuclearencoded counterparts are Ala-rich and far less hydrophobic. We speculate that this trend may reflect a need to avoid mistargeting through recognition by cytosolic signal recognition particle, which preferentially interacts with more hydrophobic signal peptides.

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Section: Resultsmentioning

confidence: 99%

Unusual Characteristics of Amino‐Terminal and Hydrophobic Domains in Nuclear‐Encoded Thylakoid Signal Peptides

Brink¹,

Bogsch²,

Mant³

et al. 1997

European Journal of Biochemistry

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“…5). This is well before the single TMS in PetA has been synthesized, but it is 65 amino acids after the signal peptide cleavage site (27). Thus, the PetA signal peptide likely anchors the translating ribosome to the thylakoid membrane cotranslationally in vivo.…”

Section: Synthesis Of Cotranslationally Targeted Proteins Initiates Omentioning

confidence: 97%

Genome-wide analysis of thylakoid-bound ribosomes in maize reveals principles of cotranslational targeting to the thylakoid membrane

Zoschke

Barkan

2015

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

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Chloroplast genomes encode ∼37 proteins that integrate into the thylakoid membrane. The mechanisms that target these proteins to the membrane are largely unexplored. We used ribosome profiling to provide a comprehensive, high-resolution map of ribosome positions on chloroplast mRNAs in separated membrane and soluble fractions in maize seedlings. The results show that translation invariably initiates off the thylakoid membrane and that ribosomes synthesizing a subset of membrane proteins subsequently become attached to the membrane in a nucleaseresistant fashion. The transition from soluble to membraneattached ribosomes occurs shortly after the first transmembrane segment in the nascent peptide has emerged from the ribosome. Membrane proteins whose translation terminates before emergence of a transmembrane segment are translated in the stroma and targeted to the membrane posttranslationally. These results indicate that the first transmembrane segment generally comprises the signal that links ribosomes to thylakoid membranes for cotranslational integration. The sole exception is cytochrome f, whose cleavable N-terminal cpSecA-dependent signal sequence engages the thylakoid membrane cotranslationally. The distinct behavior of ribosomes synthesizing the inner envelope protein CemA indicates that sorting signals for the thylakoid and envelope membranes are distinguished cotranslationally. In addition, the fractionation behavior of ribosomes in polycistronic transcription units encoding both membrane and soluble proteins adds to the evidence that the removal of upstream ORFs by RNA processing is not typically required for the translation of internal genes in polycistronic chloroplast mRNAs.ribosome profiling | protein targeting | plastid | chloroplast | SecA

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“…were unsuccessful probably due to the precursor protein folding to insertion-incompetent forms soon after synthesis (Anderson and Gray, 1991). We have circumvented this problem by importing into isolated chloroplasts the cytochrome f precursor fused to the chloroplasttargeting presequence of the small subunit of ribulose 1,5-bisphosphate carboxylase (Rubisco).…”

Section: Introductionmentioning

confidence: 99%

Azide‐sensitive thylakoid membrane insertion of chimeric cytochrome f polypeptides imported by isolated pea chloroplasts

et al. 1997

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SummaryPost-translational integration of cytochrome f into thylakoid membranes was observed after import by isolated pea chloroplasts of a chimeric protein consisting of the presequence of the small subunit of ribulose 1,5-bisphosphate carboxylase fused to the cytochrome f precursor. Import of a similar chimeric protein lacking the C-terminal 33 amino acid residues resulted in a soluble cytochrome f protein in the thylakoid lumen, indicating that the C-terminal region contains a stop-transfer sequence for membrane integration. Azide inhibited the insertion of cytochrome f into the thylakoid membrane, whereas the ionophores nigericin and valinomycin had little effect on membrane insertion. The precursor of the 33 kDa protein, but not the 23 kDa protein, of the photosystem II oxygen-evolving complex inhibited the thylakoid insertion of cytochrome f, suggesting competition for a component of the transport pathway. These experiments suggest that the post-translational insertion of cytochrome f into the thylakoid membrane uses a SecAdependent pathway.

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Cleavage of the precursor of pea chloroplast cytochrome ƒ by leader peptidase from Escherichia coli

Abstract: Vohtme 280, number 2, ~g~g6FEBS 09~]S ®m 199I Federaliol~ o1' I~urol~an [l|o~hemleal ~o~iell~s 0014~79:tt91/$~!.~0

Cited by 33 publications

References 27 publications

Unusual Characteristics of Amino‐Terminal and Hydrophobic Domains in Nuclear‐Encoded Thylakoid Signal Peptides

Unusual Characteristics of Amino‐Terminal and Hydrophobic Domains in Nuclear‐Encoded Thylakoid Signal Peptides

Genome-wide analysis of thylakoid-bound ribosomes in maize reveals principles of cotranslational targeting to the thylakoid membrane

Azide‐sensitive thylakoid membrane insertion of chimeric cytochrome f polypeptides imported by isolated pea chloroplasts

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