The Sec translocase

Plessis, David J.F. du; Nouwen, Nico; Driessen, Arnold J. M.

doi:10.1016/j.bbamem.2010.08.016

Cited by 234 publications

(210 citation statements)

References 262 publications

Supporting

Mentioning

208

Contrasting

Unclassified

Order By: Relevance

“…In E. coli, the integration of membrane proteins inside the lipid bilayer occurs via the SecYEG pathway, itself composed of membrane proteins (90). Recently, techniques to express a large amount of functional IMPs in vitro have been developed (91).…”

Section: Bottom-up Development Of An Artificial Cell: Broad Consideramentioning

confidence: 99%

Development of an artificial cell, from self-organization to computation and self-reproduction

Noireaux¹,

Maeda

Libchaber

2011

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

296

267

View full text Add to dashboard Cite

This article describes the state and the development of an artificial cell project. We discuss the experimental constraints to synthesize the most elementary cell-sized compartment that can self-reproduce using synthetic genetic information. The original idea was to program a phospholipid vesicle with DNA. Based on this idea, it was shown that in vitro gene expression could be carried out inside cell-sized synthetic vesicles. It was also shown that a couple of genes could be expressed for a few days inside the vesicles once the exchanges of nutrients with the outside environment were adequately introduced. The development of a cell-free transcription/translation toolbox allows the expression of a large number of genes with multiple transcription factors. As a result, the development of a synthetic DNA program is becoming one of the main hurdles. We discuss the various possibilities to enrich and to replicate this program. Defining a program for self-reproduction remains a difficult question as nongenetic processes, such as molecular self-organization, play an essential and complementary role. The synthesis of a stable compartment with an active interface, one of the critical bottlenecks in the synthesis of artificial cell, depends on the properties of phospholipid membranes. The problem of a self-replicating artificial cell is a long-lasting goal that might imply evolution experiments.Defining Life Since Schrödinger's classic book What Is Life? (1), the definition of life has always been a puzzle with a variety of partial answers, none really satisfying. One answer is that life is a coded system with mutation and error correction (2). The information is encoded into DNA (the genotype) and the genetic code allows translating this information into proteins (the phenotype). The genetic code is universal, and the genome can support mutations, recombination, duplication, and partial transfer from organisms to organisms. Error correction limits the risk of melting the information into random sequences. This is fine, but life is also metabolism with a permanent absorption and transformation of nutrients from the environment (3). A constant flux of energy is needed to sustain the operation of this living dynamical system out of equilibrium. But life is also self-reproduction (4). Cells originate from preexisting cells by cell division. The DNA genome is replicated, the cell self-reproduces as well as the complete organism. Is self-reproduction a constraint of evolution present at each step and imposing severe design constraints or a possible definition of life? Or is life an emerging phenomenon resulting from complex chemical reactions, developing networks and cycles until, at a certain critical size of this network, life starts as an emerging property (5)? Within this approach, life is a dynamical system where signal to noise is just marginal; a living system positions itself at the edge of chaos. Finally the only generally accepted theme is that life is the result of evolution, natural selection, and adaptation (6), a...

show abstract

Section: Bottom-up Development Of An Artificial Cell: Broad Consideramentioning

confidence: 99%

Development of an artificial cell, from self-organization to computation and self-reproduction

Noireaux¹,

Maeda

Libchaber

2011

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

296

267

View full text Add to dashboard Cite

show abstract

“…P resecretory proteins with an N-terminally attached signal sequence are translocated across the endoplasmic reticulum (ER) membranes of eukaryotes and the cytoplasmic membranes of Escherichia coli with the aid of the conservative proteinconducting channels called the Sec61 and SecYEG complexes, respectively (1)(2)(3). In E. coli, SecYEG, a translocon, and SecA, a translocation ATPase, play central roles in preprotein translocation.…”

mentioning

confidence: 99%

Glycolipozyme MPIase is essential for topology inversion of SecG during preprotein translocation

Moser

Nagamori

Huber

et al. 2013

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

View full text Add to dashboard Cite

Presecretory proteins are translocated across biological membranes through protein-conducting channels such as Sec61 (eukaryotes) and SecYEG (bacteria). SecA, a translocation ATPase, pushes preproteins out with dynamic structural changes through SecYEG. SecG, a subunit of the SecYEG channel possessing two transmembrane stretches (TMs), undergoes topology inversion coupled with SecA-dependent translocation. Recently, we characterized membrane protein integrase (MPIase), a glycolipozyme involved in not only protein integration into membranes but also preprotein translocation. We report here that SecG inversion occurs only when MPIase associates with SecYEG. We also found that MPIase modulates the dimer orientation of SecYEG. Cysteine-scanning mutagenesis mapped SecG TM 2 to a relatively hydrophilic environment. The dimer formation of SecG, crosslinked at TM 2, was not observed on SecG inversion, indicating that SecYEG undergoes a dynamic structural change during preprotein translocation.

show abstract

“…Several ion or protein channels form a membrane protein complex containing auxiliary subunits. In SecYEG complex, a translocon in bacteria, SecY is a pore-forming subunit (36). SecE, which partly participates in the pore structure, is required for the stabilization of SecY.…”

Section: Discussionmentioning

confidence: 99%

Contribution of the γ-Secretase Subunits to the Formation of Catalytic Pore of Presenilin 1 Protein

Takeo

Watanabe

Tomita

et al. 2012

Journal of Biological Chemistry

View full text Add to dashboard Cite

Background: ␥-Secretase, which is composed of presenilin and three subunits, is an intramembrane-cleaving protease related to Alzheimer disease. Results: Water accessibility of the catalytic pore of presenilin was decreased during assembly of active ␥-secretase. Conclusion: Binding of the subunits allosterically contributes to the formation of catalytic pore. Significance: The ␥-secretase subunits modulate the structure of presenilin.

show abstract

The Sec translocase

Cited by 234 publications

References 262 publications

Development of an artificial cell, from self-organization to computation and self-reproduction

Development of an artificial cell, from self-organization to computation and self-reproduction

Glycolipozyme MPIase is essential for topology inversion of SecG during preprotein translocation

Contribution of the γ-Secretase Subunits to the Formation of Catalytic Pore of Presenilin 1 Protein

Contact Info

Product

Resources

About