The Bacterial Protein–Translocation Complex: SecYEG Dimers Associate with One or Two SecA Molecules

Tziatzios, Christos; Schubert, Dieter; Lotz, Mirko; Gundogan, Derya; Betz, Heidi; Schägger, Hermann; Haase, Winfried; Duong, Franck; Collinson, Ian

doi:10.1016/j.jmb.2004.04.076

Cited by 58 publications

(62 citation statements)

References 43 publications

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“…The membrane bound and active version of SecYEG is dimeric (11)(12)(13)(14), but only one copy is necessary to create the channel (15). We show that CL, and to a lesser degree PG, promotes the formation of SecYEG dimers and a high-affinity binding surface for SecA.…”

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confidence: 84%

The action of cardiolipin on the bacterial translocon

Gold

Robson

Bao

et al. 2010

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

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Cardiolipin is an ever-present component of the energy-conserving inner membranes of bacteria and mitochondria. Its modulation of the structure and dynamism of the bilayer impacts on the activity of their resident proteins, as a number of studies have shown. Here we analyze the consequences cardiolipin has on the conformation, activity, and localization of the protein translocation machinery. Cardiolipin tightly associates with the SecYEG protein channel complex, whereupon it stabilizes the dimer, creates a high-affinity binding surface for the SecA ATPase, and stimulates ATP hydrolysis. In addition to the effects on the structure and function, the subcellular distribution of the complex is modified by the cardiolipin content of the membrane. Together, the results provide rare and comprehensive insights into the action of a phospholipid on an essential transport complex, which appears to be relevant to a broad range of energy-dependent reactions occurring at membranes.

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mentioning

confidence: 84%

The action of cardiolipin on the bacterial translocon

Gold

Robson

Bao

et al. 2010

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

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150

153

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“…[55][56][57][58]. The application of this method to the study of GARP2 in the absence of detergent is shown in Fig.…”

Section: Nmr and CD Investigations Of Peptides Corresponding To The Rmentioning

confidence: 99%

“…Lower panel, local differences of ⌬A(r) between experimental and fitted data. C, evaluation of the statistical accuracy for the calculated relative absorbance contribution of the different GARP2 oligomers: changes in the sum of the squared residuals, , of the fits to the data from B that result from one nonoptimal absorbance parameter (37,39,57). The minima of the curves correspond to the best-fit values for the relative concentration of each GARP2 oligomer in the sample.…”

Section: Nmr and CD Investigations Of Peptides Corresponding To The Rmentioning

confidence: 99%

Glutamic Acid-rich Proteins of Rod Photoreceptors Are Natively Unfolded

Batra‐Safferling

Abarca-Heidemann

Körschen

et al. 2006

Journal of Biological Chemistry

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The outer segment of vertebrate photoreceptors is a specialized compartment that hosts all the signaling components required for visual transduction. Specific to rod photoreceptors is an unusual set of three glutamic acid-rich proteins (GARPs) as follows: two soluble forms, GARP1 and GARP2, and the N-terminal cytoplasmic domain (GARP part) of the B1 subunit of the cyclic GMP-gated channel. GARPs have been shown to interact with proteins at the rim of the disc membrane. Here we characterized native GARP1 and GARP2 purified from bovine rod photoreceptors. Amino acid sequence analysis of GARPs revealed structural features typical of "natively unfolded" proteins. By using biophysical techniques, including size-exclusion chromatography, dynamic light scattering, NMR spectroscopy, and circular dichroism, we showed that GARPs indeed exhibit a large degree of intrinsic disorder. Analytical ultracentrifugation and chemical cross-linking showed that GARPs exist in a monomer/multimer equilibrium. The results suggested that the function of GARP proteins is linked to their structural disorder. They may provide flexible spacers or linkers tethering the cyclic GMP-gated channel in the plasma membrane to peripherin at the disc rim to produce a stack of rings of these protein complexes along the long axis of the outer segment. GARP proteins could then provide the environment needed for protein interactions in the rim region of discs.

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“…This is further complicated by the different models suggesting association of both the monomeric and dimeric forms of SecA to the SecYEG translocon (27)(28)(29)(30), although the structure of the SecA-SecYEG complex suggests a 1:1 interaction (10). The structure of the SecA-SecYEG complex was a major achievement, but it failed to explain the observed interactions between SecA and SecYEG during translocation (10,(31)(32)(33). SecA alone has also been suggested to promote protein translocation independently of SecYEG (34 -36).…”

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confidence: 99%