Precursor protein translocation by the Escherichia coli translocase is directed by the protonmotive force.

Driessen, Arnold J.M.

doi:10.1002/j.1460-2075.1992.tb05122.x

Cited by 112 publications

(106 citation statements)

References 56 publications

(82 reference statements)

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“…Not surprisingly, dissipation of the protonmotive force caused the number of ATPs hydrolyzed per protein transported to increase from ∼700 to 5,000 or more (14). It was later determined that a single energy-dependent step for the Sec translocon results in the transport of about 50 amino acids of an unfolded linear substrate (43), which is consistent with an independent measurement of 5 ATP hydrolyzed per amino acid transported (44).…”

Section: Discussioncontrasting

confidence: 38%

“…Without this information, it is not possible to assess the amount of metabolic energy that is spent on the cell's considerable protein trafficking activity. One such measurement of the energy required for protein transport is the so-called translocation ATPase activity of the bacterial Sec pathway observed with inverted plasma membrane vesicles from Escherichia coli (14,15). In these experiments it was found that ∼700 ATP molecules were hydrolyzed per prOmpA molecule exported when the membranes were allowed to develop a protonmotive force.…”

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confidence: 45%

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Energetic cost of protein import across the envelope membranes of chloroplasts

Shi

Theg

2012

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

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Chloroplasts are the organelles of green plants in which light energy is transduced into chemical energy, forming ATP and reduced carbon compounds upon which all life depends. The expenditure of this energy is one of the central issues of cellular metabolism. Chloroplasts contain ∼3,000 proteins, among which less than 100 are typically encoded in the plastid genome. The rest are encoded in the nuclear genome, synthesized in the cytosol, and posttranslationally imported into the organelle in an energy-dependent process. We report here a measurement of the amount of ATP hydrolyzed to import a protein across the chloroplast envelope membranesonly the second complete accounting of the cost in Gibbs free energy of protein transport to be undertaken. Using two different precursors prepared by three distinct techniques, we show that the import of a precursor protein into chloroplasts is accompanied by the hydrolysis of ∼650 ATP molecules. This translates to a ΔG protein transport of some 27,300 kJ/mol protein imported. We estimate that protein import across the plastid envelope membranes consumes ∼0.6% of the total light-saturated energy output of the organelle. T he majority of proteins in cells are synthesized in the cytoplasm on free or membrane-bound ribosomes. The fraction of proteins that are translocated across one or more cellular membranes has been estimated to be almost 50% in eukaryotic cells (1) and as high as 30% in bacteria (2, 3). Thus, protein movement out of the cytoplasm across membranes represents a considerable cellular activity involving numerous and varied protein transport systems. Protein translocation across membranes is also generally an energy-requiring process, making it a potentially costly activity for cells (4).The nature of the energy inputs to the different protein translocation systems has been extensively studied. We know, for example, that the posttranslational transport of proteins into the endoplasmic reticulum requires ATP hydrolysis alone (4-6), and that the transport of proteins into the thylakoid lumen or across the bacterial plasma membrane on the Tat pathway requires only the transmembrane protonmotive force with no contribution of ATP hydrolysis (7,8). A more complex energy input is required for many other protein transport systems. For instance, the import of proteins into the mitochondrial matrix requires both ATP hydrolysis and the Δψ across the inner mitochondrial membrane (9-11), and bacterial secretion and protein transport to the thylakoid lumen on their respective Sec pathways use ATP hydrolysis and the protonmotive force (3,7,12,13).In contrast to the abundance of work defining the nature of the energy driving protein transporters, few attempts have been made to quantitate the amount of energy required for these reactions. Without this information, it is not possible to assess the amount of metabolic energy that is spent on the cell's considerable protein trafficking activity. One such measurement of the energy required for protein transport is the so-called translo...

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Section: Discussioncontrasting

confidence: 38%

mentioning

confidence: 45%

Energetic cost of protein import across the envelope membranes of chloroplasts

Shi

Theg

2012

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

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“…In general, the two main sources are chemical energy (ATP, GTP) and electrochemical energy (PMF) (129,130). Whereas GTP is the main driving force during Sec co-translational protein translocation, ATP is the main source of energy utilized during the Sec post-translational route.…”

Section: Protein Translocation Energeticssupporting

confidence: 46%

“…Interestingly while ATP is essential for initiation of Sec mediated translocation, depending on the substrate, translocation may be further stimulated by the PMF (128,131). Although the PMF cannot initiate translocation, PMF-driven translocation is highly efficient in the absence of SecA, and it is suggested that the PMF acts as a driving force possibly involving vectorial proton movements (129,130).…”

Section: Protein Translocation Energeticssupporting

confidence: 40%

Assembly pathway of a bacterial complex iron sulfur molybdoenzyme

Cherak

Turner

2017

Biomolecular Concepts

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Protein folding and assembly into macromolecule complexes within the living cell are complex processes requiring intimate coordination. The biogenesis of complex iron sulfur molybdoenzymes (CISM) requires use of a system specific chaperone -a redox enzyme maturation protein (REMP) -to help mediate final folding and assembly. The CISM dimethyl sulfoxide (DMSO) reductase is a bacterial oxidoreductase that utilizes DMSO as a final electron acceptor for anaerobic respiration. The REMP DmsD strongly interacts with DMSO reductase to facilitate folding, cofactor-insertion, subunit assembly and targeting of the multi-subunit enzyme prior to membrane translocation and final assembly and maturation into a bioenergetic catalytic unit. In this article, we discuss the biogenesis of DMSO reductase as an example of the participant network for bacterial CISM maturation pathways.

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“…ATP-binding leads to the membrane insertion of one segment (about 30 residues) of polypeptide, and this is released upon ATP hydrolysis. Although complete translocation is possible by repeated cycles of this ATP-driven movement (Wickner et al 1991), the rapid translocation of polypeptide after its release from SecA, is likely to be driven by the proton motive force (Driessen 1992). Speed is essential because the total number of SecY complexes in an E. coli cell is only about 500, and these must cope with the cell envelope localization of 10 6 molecules in one generation (Matsuyama et al 1992).…”

Section: What Powers Protein Translocationmentioning

confidence: 99%

The major pathways of protein translocation across membranes

Ito

1996

Genes to Cells

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The initial events in the localization of cell surface proteins include targeting of precursor molecules to the membrane and subsequent translocation across the membrane. The translocation reaction is mediated through a series of molecular interactions involving a number of protein factors. The trimeric SecY/Sec61 core complex, which is conserved throughout evolution, provides a proteinaceous pathway for translocation. The driving force for translocation is provided by the dynamic motion of the SecA ATPase in prokaryotes and by polypeptide elongation through the ribosome-Sec61 junction in eukaryotes.

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Precursor protein translocation by the Escherichia coli translocase is directed by the protonmotive force.

Cited by 112 publications

References 56 publications

Energetic cost of protein import across the envelope membranes of chloroplasts

Energetic cost of protein import across the envelope membranes of chloroplasts

Assembly pathway of a bacterial complex iron sulfur molybdoenzyme

The major pathways of protein translocation across membranes

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