Crystal structure of the bacterial membrane protein TolC central to multidrug efflux and protein export

Koronakis, Vassilis; Sharff, A.; Koronakis, Eva; Luisi, Ben F.; Hughes, Colin

doi:10.1038/35016007

Cited by 986 publications

(1,050 citation statements)

References 39 publications

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“…However, the T-shaped complex in the preparation was never observed in any of the previously studied PS I samples (Kruip et al 1997). Its shape is distantly reminiscent of a recently described TolC protein from gram-negative bacteria spanning both the outer membrane and the periplasmic space (Koronakis et al 2000). This protein has an overall length of 14 nm, of which nearly 10 nm consists of a uniform cylinder of about 35 Å internal diameter.…”

Section: Electron Microscopymentioning

confidence: 77%

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Mangels

Kruip

Berry

et al. 2002

Photosynthesis Research

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Photosystem I from the unusual cyanobacterium Gloeobacter violaceus Mangels, D.; Kruip, J.; Berry, S.; Rögner, M.; Boekema, E.J.; Koenig, F. Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Key words: antenna system, electron microscopy, fluorescence, light harvesting, photosynthesis, plasma membrane AbstractPhotosystem I (PS I) from the primitive cyanobacterium Gloeobacter violaceus has been purified and characterised. Despite the fact that the isolated complexes have the same subunit composition as complexes from other cyanobacteria, the amplitude of flash-induced absorption difference spectra indicates a much bigger antenna size with about 150 chlorophylls per P700 as opposed to the usual 90. Image analysis of the PS I preparation from Gloeobacter reveals that the PS I particles exist both in a trimeric and in a monomeric form and that their size and shape closely resembles other cyanobacterial PS I particles. However, the complexes exhibit a higher molecular weight as could be shown by gel filtration. The preparation contains novel polypeptides not related to known Photosystem I subunits. The N-terminal sequence of one of those polypeptides has been determined and reveals no homology to known or hypothetical proteins. Immunoblotting shows a cross-reaction of three of the polypeptide bands with an antibody raised against the major LHC from the diatom Cyclotella cryptica. Electron microscopy reveals a novel T-shaped complex which has never been observed in any other cyanobacterial PS I preparation. 77 K spectra of purified PS I show an extreme blue-shift of the fluorescence emission, indicating an unusual organisation of the PS I antenna system in Gloeobacter.Abbreviations: PS -photosystem; Chl -chlorophyll; DM -dodecyl-β-D-maltoside; ECL -enhanced chemiluminescence; HPLC -high performance liquid chromatography; IEC -ion exchange chromatography; GF -gel filtration; LHC I -light harvesting complex associated with Photosystem I; P700 -primary electron donor of photosystem I; SDS -sodium dodecyl sulfate; SQDG -sulfoquinovosyl diacylglycerol; PAGE -polyacrylamide gel electrophoresis; F760 (F730) -fluorescence band with maximal emission at 760 nm (730 nm)

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Section: Electron Microscopymentioning

confidence: 77%

Untitled

Mangels

Kruip

Berry

et al. 2002

Photosynthesis Research

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“…Surface-exposed RsaA protein was extracted with acid as described by Koronakis et al (2000). RsaA was visualized using SDS-PAGE and Western blotting using antiRsaA antiserum (Toporowski et al, 2004; 1 : 10 000).…”

Section: Methodsmentioning

confidence: 99%

“…5a). RsaF a and RsaF b are expected to function as trimers, similar to TolC (Koronakis et al, 2000). To determine if the RsaF proteins in the DbamE mutant are competent to secrete RsaA, we isolated surfaceexposed RsaA protein by low-pH extraction (Koronakis et al, 2000).…”

Section: Membranes Of Dbame Cells Are Deficient In Some Ompsmentioning

confidence: 99%

The BAM complex subunit BamE (SmpA) is required for membrane integrity, stalk growth and normal levels of outer membrane β-barrel proteins in Caulobacter crescentus

2010

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The outer membrane of Gram-negative bacteria is an essential compartment containing a specific complement of lipids and proteins that constitute a protective, selective permeability barrier. Outer membrane β-barrel proteins are assembled into the membrane by the essential hetero-oligomeric BAM complex, which contains the lipoprotein BamE. We have identified a homologue of BamE, encoded by CC1365, which is located in the outer membrane of the stalked alpha-proteobacterium Caulobacter crescentus. BamE associates with proteins whose homologues in other bacteria are known to participate in outer membrane protein assembly: BamA (CC1915), BamB (CC1653) and BamD (CC1984). Caulobacter cells lacking BamE grow slowly in rich medium and are hypersensitive to anionic detergents, some antibiotics and heat exposure, which suggest that the membrane integrity of the mutant is compromised. Membranes of the ΔbamE mutant have normal amounts of the outer membrane protein RsaF, a TolC homologue, but are deficient in CpaC*, an aggregated form of the outer membrane secretin for type IV pili. ΔbamE membranes also contain greatly reduced amounts of three TonB-dependent receptors that are abundant in wild-type cells. Cells lacking BamE have short stalks and are delayed in stalk outgrowth during the cell cycle. Based on these findings, we propose that Caulobacter BamE participates in the assembly of outer membrane β-barrel proteins, including one or more substrates required for the initiation of stalk biogenesis.

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“…CvaA is anchored in the cytoplasmic membrane and mainly located in the periplasm, where it serves as a connector or membrane fusion protein to the outer-membrane protein TolC. The ABC transporter CvaB is connected by CvaA to the trimeric outer-membrane protein TolC, which forms a single bbarrel in the outer membrane with a bundle of a-helices extending into the periplasm (Koronakis et al, 2000). The CvaA/CvaB/TolC channel allows the secretion of microcins across two membranes, which is a general feature of these RND-type exporters (Tseng et al, 1999).…”

Section: Identification Of the Microcin-encoding Gene Clustermentioning

confidence: 99%

The colicin G, H and X determinants encode microcins M and H47, which might utilize the catecholate siderophore receptors FepA, Cir, Fiu and IroN

et al. 2003

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The colicin G producer Escherichia coli CA46, the colicin H producer E. coli CA58 and E. coli Nissle 1917 (DSM 6601) were shown to produce microcin H47 and the newly described microcin M. Both microcins were exported like colicin V by an RND-type export system, including TolC. The gene cluster encoding microcins H47 and M in strains CA46 and CA58 is nearly identical to that in strain DSM 6601, except that two additional genes are included. A Fur box identified in front of the microcin-encoding genes explained the observed iron regulation of microcin production. The catecholate siderophore receptors Fiu, Cir and FepA from E. coli and IroN, Cir and FepA from Salmonella were identified as receptors for microcins M, H47 and E492. IroN takes up the glucose-containing catecholate siderophore salmochelin, whose synthesis is encoded in the iro gene cluster found in Salmonella and certain, often uropathogenic, E. coli strains. A gene in this iro cluster, iroB, which encodes a putative glycosyltransferase, was also found in the microcin H47/M and microcin E492 gene clusters. These microcins could aid the producing strain in competing against enterobacteria that utilize catecholate siderophores.

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Crystal structure of the bacterial membrane protein TolC central to multidrug efflux and protein export

Cited by 986 publications

References 39 publications

Untitled

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The BAM complex subunit BamE (SmpA) is required for membrane integrity, stalk growth and normal levels of outer membrane β-barrel proteins in Caulobacter crescentus

The colicin G, H and X determinants encode microcins M and H47, which might utilize the catecholate siderophore receptors FepA, Cir, Fiu and IroN

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