Structure of the outer membrane protein A transmembrane domain

Pautsch, Alexander; Schulz, Georg E.

doi:10.1038/2983

Cited by 458 publications

(403 citation statements)

References 39 publications

(31 reference statements)

Supporting

Mentioning

382

Contrasting

Unclassified

Order By: Relevance

“…To calculate the chemical shift efficiently, the chemical shift tensor needs to be fixed relative to a local molecular frame, and the magnitude of each component must be constant, which is the so-called "rigid tensor approximation" [17,18]. Because the SSNMR time scale is much longer than that of molecular motions, the observed chemical shift (σ exp ) parallel to the magnetic field can be calculated as a time-average of the projected instantaneous second-rank tensor, (5) where n̂ is a unit vector of the magnetic field, which is assumed to be parallel to the membrane normal (the Z-axis; n̂ ≡ ẑ), and σ ii (t) and ê i (t) are the instantaneous magnitude and unit vector of chemical shift tensors, respectively. In general, ê 1 and ê 3 are on the peptide plane defined by N, C, and H atoms, and ê 2 is defined by the cross product of r NC and r NH [18].…”

Section: Ssnmr Chemical Shiftmentioning

confidence: 99%

“…Identifying and characterizing the relative orientation of helices in membrane proteins are crucial in determining their topologies and three-dimensional structures, which can provide insights into the underlying pathologic mechanisms responsible for many human diseases. Although particular successes are evident for some membrane proteins [4][5][6], X-ray diffraction methods generally encounter numerous obstacles due to hydrophobic interactions between membrane proteins and lipids. Solid-state NMR (SSNMR) is an emerging technique to study the topology, structure, and dynamics of membrane proteins in their native environment of lipid bilayers, which can complement X-ray and solution NMR studies.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Application of solid-state NMR restraint potentials in membrane protein modeling

Lee

Chen

Brooks

et al. 2008

Journal of Magnetic Resonance

View full text Add to dashboard Cite

We have developed a set of orientational restraint potentials for solid-state NMR observables including 15 N chemical shift and 15 N-1 H dipolar coupling. Torsion angle molecular dynamics simulations with available experimental 15 N chemical shift and 15 N-1 H dipolar coupling as target values have been performed to determine orientational information of four membrane proteins and to model the structures of some of these systems in oligomer states. The results suggest that incorporation of the orientational restraint potentials into molecular dynamics provides an efficient means to the determination of structures that optimally satisfy the experimental observables without an extensive geometrical search.

show abstract

Section: Ssnmr Chemical Shiftmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Application of solid-state NMR restraint potentials in membrane protein modeling

Lee

Chen

Brooks

et al. 2008

Journal of Magnetic Resonance

View full text Add to dashboard Cite

show abstract

“…The different structures are characterized by TM b strands that span the lipid bilayer with an angle of ~45°and often extend into the LPS region of the outer membrane. TM b barrels have an even number of antiparallel TM strands, which is 8 for OmpA [69], 12 for OmPlA [8], 18 for ScrY [11] and 22 for FhuA [12]. OmpA is a small ion channel [29], ScrY is a sucrose-specific porin that forms trimers, FhuA is an active transporter for iron-uptake and OmPlA a phospholipase that forms a dimer.…”

Section: In Vitro Requirements For Membrane Protein Foldingmentioning

confidence: 99%

“…Using this method, previously unidentified folding intermediates on the pathway of OmpA insertion and folding into lipid bilayers can be detected, trapped and characterized. Three membrane-bound intermediates have been described, in which the average distances of the Trps from the bilayer center are 14-16 Å, 10-11 Å and 0-5 Å, respectively [62] [5,6,69] and according to experiments with single Trp mutants of OmpA [61] (see below), Trp-7 has to remain in the first leaflet of the lipid bilayer, while the other Trps have to be translocated across the bilayer to the second leaflet. When folding is monitored by KTSE experiments at 28-30°C, a 32-kDa band can be observed in the first few minutes of the OmpA folding reaction [30].…”

Section: Identification and Characterization Of Membranebound Foldingmentioning

confidence: 99%

Membrane protein folding on the example of outer membrane protein A of Escherichia coli

Kleinschmidt¹

2003

Cellular and Molecular Life Sciences (CMLS)

View full text Add to dashboard Cite

Abstract. The biophysical principles and mechanisms by which membrane proteins insert and fold into a biomembrane have mostly been studied with bacteriorhodopsin and outer membrane protein A (OmpA). This review describes the assembly process of the monomeric outer membrane proteins of Gram-negative bacteria, for which OmpA has served as an example. OmpA is a two-domain outer membrane protein composed of a 171-residue eight-stranded b-barrel transmembrane domain and a 154-residue periplasmic domain. OmpA is translocated in an unstructured form across the cytoplasmic membrane into the periplasm. In the periplasm, unfolded OmpA is kept in solution in complex with the molecular chaperone Skp. After binding of periplasmic lipopolysaccharide, OmpA insertion and folding occur spontaneously upon interaction of the complex with the phospholipid bilayer. Insertion and folding of the b-barrel transmembrane domain into the lipid bilayer are highly synchronized, i.e. the formation of large amounts of b-sheet secondary structure and b-barrel tertiary structure take place in parallel with the same rate constants, while OmpA inserts into the hydrophobic core of the membrane. In vitro, OmpA can successfully fold into a range of model membranes of very different phospholipid compositions, i.e. into bilayers of lipids of different headgroup structures and hydrophobic chain lengths. Three membrane-bound folding intermediates of OmpA were discovered in folding studies with dioleoylphosphatidylcholine bilayers. Their formation was monitored by time-resolved distance determinations by fluorescence quenching, and they were structurally distinguished by the relative positions of the five tryptophan residues of OmpA in projection to the membrane normal. Recent studies indicate a chaperone-assisted, highly synchronized mechanism of secondary and tertiary structure formation upon membrane insertion of b-barrel membrane proteins such as OmpA that involves at least three structurally distinct folding intermediates.

show abstract

“…OmpA loops, which mediate bacterial entry into hBMECs, have been identified [31,33]. Thus, it is possible that a transmembrane protein facilitates the association with and invasion into hBMECs.…”

Section: Discussionmentioning

confidence: 99%

Competence-induced protein Ccs4 facilitates pneumococcal invasion into brain tissue and virulence in meningitis

et al. 2018

View full text Add to dashboard Cite

Streptococcus pneumoniae is a major pathogen that causes pneumonia, sepsis, and meningitis. The candidate combox site 4 (ccs4) gene has been reported to be a pneumococcal competence-induced gene. Such genes are involved in development of S. pneumoniae competence and virulence, though the functions of ccs4 remain unknown. In the present study, the role of Ccs4 in the pathogenesis of pneumococcal meningitis was examined. We initially constructed a ccs4 deletion mutant and complement strains, then examined their association with and invasion into human brain microvascular endothelial cells. Wild-type and Ccs4-complemented strains exhibited significantly higher rates of association and invasion as compared to the ccs4 mutant strain. Deletion of ccs4 did not change bacterial growth activity or expression of NanA and CbpA, known brain endothelial pneumococcal adhesins. Next, mice were infected either intravenously or intranasally with pneumococcal strains. In the intranasal infection model, survival rates were comparable between wild-type strain-infected and ccs4 mutant strain-infected mice, while the ccs4 mutant strain exhibited a lower level of virulence in the intravenous infection model. In addition, at 24 hours after intravenous infection, the bacterial burden in blood was comparable between the wild-type and ccs4 mutant strain-infected mice, whereas the wild-type strain-infected mice showed a significantly higher bacterial burden in the brain. These results suggest that Ccs4 contributes to pneumococcal invasion of host brain tissues and functions as a virulence factor.

show abstract

Structure of the outer membrane protein A transmembrane domain

Cited by 458 publications

References 39 publications

Application of solid-state NMR restraint potentials in membrane protein modeling

Application of solid-state NMR restraint potentials in membrane protein modeling

Membrane protein folding on the example of outer membrane protein A of Escherichia coli

Competence-induced protein Ccs4 facilitates pneumococcal invasion into brain tissue and virulence in meningitis

Contact Info

Product

Resources

About