Translocation of proteins across archaeal cytoplasmic membranes

Pohlschröder, Mechthild; Dilks, Kieran; Hand, Nicholas J.; Rose, Raymond W.

doi:10.1016/j.femsre.2003.07.004

Cited by 42 publications

(48 citation statements)

References 224 publications

(306 reference statements)

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“…The SecY, SecE, and Sec61␤ proteins that form the core of the translocation apparatus are closer to their eucaryal than their bacterial homologues (49,155,223,347,357,361). The recent solution of the threedimensional structure of the Methanococcus jannaschii SecYE␤ translocon has provided major insight into the translocation event across evolution, including the mode of translocon gating and mechanism of membrane protein insertion (446).…”

Section: Archaeal Signal Sequencesmentioning

confidence: 99%

Posttranslational Protein Modification inArchaea

Eichler

Adams

2005

Microbiol Mol Biol Rev

194

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One of the first hurdles to be negotiated in the postgenomic era involves the description of the entire protein content of the cell, the proteome. Such efforts are presently complicated by the various posttranslational modifications that proteins can experience, including glycosylation, lipid attachment, phosphorylation, methylation, disulfide bond formation, and proteolytic cleavage. Whereas these and other posttranslational protein modifications have been well characterized in Eucarya and Bacteria, posttranslational modification in Archaea has received far less attention. Although archaeal proteins can undergo posttranslational modifications reminiscent of what their eucaryal and bacterial counterparts experience, examination of archaeal posttranslational modification often reveals aspects not previously observed in the other two domains of life. In some cases, posttranslational modification allows a protein to survive the extreme conditions often encountered by Archaea. The various posttranslational modifications experienced by archaeal proteins, the molecular steps leading to these modifications, and the role played by posttranslational modification in Archaea form the focus of this review

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Section: Archaeal Signal Sequencesmentioning

confidence: 99%

Posttranslational Protein Modification inArchaea

Eichler

Adams

2005

Microbiol Mol Biol Rev

194

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“…Archaeal flagellins are believed to cross the cytoplasmic membrane, most likely via a Sec secretion pathway, and so would be exposed to a processing environment similar to that of the S-layer proteins ( [33][34][35]. Interestingly in C. jejuni an N-linked glycosylation pathway has been described that was shown to glycosylate a diverse group of cell surface and periplasmic proteins with a unique oligosaccharide (20,36).…”

Section: Nano-lc-ms/ms Analysis Of Flagellin Peptidementioning

confidence: 99%

Identification and Characterization of the Unique N-Linked Glycan Common to the Flagellins and S-layer Glycoprotein of Methanococcus voltae

Voisin

Houliston

Kelly

et al. 2005

Journal of Biological Chemistry

130

144

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The flagellum of Methanococcus voltae is composed of four structural flagellin proteins FlaA, FlaB1, FlaB2, and FlaB3. These proteins possess a total of 15 potential N-linked sequons (NX(S/T)) and show a mass shift on an SDS-polyacrylamide gel indicating significant posttranslational modification. We describe here the structural characterization of the flagellin glycan from M. voltae using mass spectrometry to examine the proteolytic digests of the flagellin proteins in combination with NMR analysis of the purified glycan using a sensitive, cryogenically cooled probe. Nano-liquid chromatography-tandem mass spectrometry analysis of the proteolytic digests of the flagellin proteins revealed that they are post-translationally modified with a novel Nlinked trisaccharide of mass 779 Da that is composed of three sugar residues with masses of 318, 258, and 203 Da, respectively. In every instance the glycan is attached to the peptide through the asparagine residue of a typical N-linked sequon. The glycan modification has been observed on 14 of the 15 sequon sites present on the four flagellin structural proteins. The novel glycan structure elucidated by NMR analysis was shown to be a trisaccharide composed of ␤-ManpNAcA6Thr-(1-4)-␤-GlcpNAc3NAcA-(1-3)-␤-GlcpNAc linked to Asn. In addition, the same trisaccharide was identified on a tryptic peptide of the S-layer protein from this organism implicating a common N-linked glycosylation pathway.Glycosylation of prokaryotic proteins is now well accepted, and examples of N-and O-glycosylation and of attachment of glycosylphosphatidylinositol anchors can now be found in the literature (1, 2). However, in contrast to eukaryotic glycosylation systems, prokaryotic systems display considerable diversity in the structure of the respective glycans and the proximal monosaccharide linkage. As a consequence there is considerable interest in determining the structural and genetic basis of glycan production among these diverse prokaryotic systems.The archaeal flagellum is a unique motility structure that is distinct from the well characterized bacterial flagellum (3). In contrast to bacterial flagellar assembly where newly synthesized flagellin is incorporated at the distal tip of the filament, it is believed that mature archaeal flagellin is incorporated at the base of the filament. In recent studies, the assembly of archaeal flagellum has been shown to more closely resemble a second bacterial motility system, the type IV pilus, where the structural protein pilin is synthesized with an unusual signal peptide and a hydrophobic N terminus. In Archaea, signal peptidases have been shown to cleave a signal peptide of the preflagellin proteins to produce mature flagellin, which is then incorporated into the filament (4). Flagellated archaeal species have one to five flagellin genes organized into a fla locus (3). The marine archaeon Methanococcus voltae has four flagellin structural genes organized in two transcriptional units: one unit contains flaA, whereas the second unit contains flaB1, flaB...

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“…The greatest detail is known about how proteins traverse the membrane by way of the universally conserved Sec pathway. Proteins that are secreted via this pathway are targeted to a membrane-embedded Sec pore by virtue of an N-terminal secretion signal and are subsequently threaded though the pore in a linear unfolded conformation (18,21). Although the vast majority of secretory proteins are translocated via the Sec pathway in most prokaryotes, it is apparent that alternative translocation mechanisms are playing crucial roles in the process of secretion in many organisms (23).…”

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confidence: 99%

Genetic and Biochemical Analysis of the Twin-Arginine Translocation Pathway in Halophilic Archaea

2005

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The twin-arginine translocation (Tat) pathway is present in a wide variety of prokaryotes and is capable of exporting partially or fully folded proteins from the cytoplasm. Although diverse classes of proteins are transported via the Tat pathway, in most organisms it facilitates the secretion of a relatively small number of substrates compared to the Sec pathway. However, computational evidence suggests that haloarchaea route nearly all secreted proteins to the Tat pathway. We have expanded previous computational analyses of the haloarchaeal Tat pathway and initiated in vivo characterization of the Tat machinery in a model haloarchaeon, Haloferax volcanii. Consistent with the predicted usage of the this pathway in the haloarchaea, we determined that three of the four identified tat genes in Haloferax volcanii are essential for viability when grown aerobically in complex medium. This represents the first report of an organism that requires the Tat pathway for viability when grown under such conditions. Deletion of the nonessential gene had no effect on the secretion of a verified substrate of the Tat pathway. The two TatA paralogs TatAo and TatAt were detected in both the membrane and cytoplasm and could be copurified from the latter fraction. Using size exclusion chromatography to further characterize cytoplasmic and membrane TatA proteins, we find these proteins present in high-molecularweight complexes in both cellular fractions.

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Translocation of proteins across archaeal cytoplasmic membranes

Cited by 42 publications

References 224 publications

Posttranslational Protein Modification inArchaea

Posttranslational Protein Modification inArchaea

Identification and Characterization of the Unique N-Linked Glycan Common to the Flagellins and S-layer Glycoprotein of Methanococcus voltae

Genetic and Biochemical Analysis of the Twin-Arginine Translocation Pathway in Halophilic Archaea

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