Read by QxMD icon Read

Beta barrell membrane protein

Max J Temple, Fiona Cuskin, Arnaud Baslé, Niall Hickey, Gaetano Speciale, Spencer J Williams, Harry J Gilbert, Elisabeth C Lowe
Glycans are major nutrients available to the human gut microbiota (HGM). The Bacteroides are generalist glycan degraders and this function is mediated largely by polysaccharide utilization loci (PULs). The genomes of several Bacteroides species contain a PUL, PUL1,6-beta;-glucan, that was predicted to target mixed linked plant 1,3;1,4-beta-glucans. To test this hypothesis we characterized the proteins encoded by this locus in Bacteroides thetaiotaomicron, a member of the HGM. We show here that PUL1,6-β-glucan does not orchestrate the degradation of a plant polysaccharide but targets a fungal cell wall glycan, 1,6-beta-glucan, which is a growth substrate for the bacterium...
May 1, 2017: Journal of Biological Chemistry
Mahnoush Babaei, Isaac C Jones, Kaushik Dayal, Meagan S Mauter
The behavior of large, complex molecules in the presence of magnetic fields is experimentally challenging to measure and computationally intensive to predict. This work proposes a novel, mixed-methods approach for efficiently computing the principal magnetic susceptibilities and diamagnetic anisotropy of membrane proteins. The hierarchical primary (amino acid), secondary (α helical and β sheet), and tertiary (α helix and β barrel) structure of transmembrane proteins enables analysis of a complex molecule using discrete subunits of varying size and resolution...
April 25, 2017: Journal of Chemical Theory and Computation
Abigail I Fish, Sean P Riley, Birendra Singh, Kristian Riesbeck, Juan J Martinez
Spotted fever group (SFG) Rickettsia species are inoculated into the mammalian bloodstream by hematophagous arthropods. Once in the bloodstream and during dissemination, the survival of these pathogens is dependent upon the ability of these bacteria to evade serum-borne host defenses until a proper cellular host is reached. Rickettsia conorii expresses an outer membrane protein, Adr1, which binds the complement inhibitory protein vitronectin to promote resistance to the anti-bacterial effects of the terminal complement complex...
2017: Frontiers in Cellular and Infection Microbiology
Michael G Gresock, Kathleen Postle
In Gram-negative bacteria, the cytoplasmic membrane protein TonB transmits energy derived from proton motive force to energize transport of important nutrients through TonB-dependent transporters in the outer membrane. Each transporter consists of a beta barrel domain and a lumen-occluding cork domain containing an essential sequence called the TonB box. To date, the only identified site of transporter-TonB interaction is between the TonB box and residues ∼158 to 162 of TonB. While the mechanism of ligand transport is a mystery, a current model based on site-directed spin labeling and molecular dynamics simulations is that, following ligand binding, the otherwise-sequestered TonB box extends into the periplasm for recognition by TonB, which mediates transport by pulling or twisting the cork...
May 15, 2017: Journal of Bacteriology
Georgios N Tsaousis, Stavros J Hamodrakas, Pantelis G Bagos
Transmembrane beta-barrels (TMBBs) constitute an important structural class of membrane proteins located in the outer membrane of gram-negative bacteria, and in the outer membrane of chloroplasts and mitochondria. They are involved in a wide variety of cellular functions and the prediction of their transmembrane topology, as well as their discrimination in newly sequenced genomes is of great importance as they are promising targets for antimicrobial drugs and vaccines. Several methods have been applied for the prediction of the transmembrane segments and the topology of beta barrel transmembrane proteins utilizing different algorithmic techniques...
2017: Methods in Molecular Biology
Wei Tian, Meishan Lin, Hammad Naveed, Jie Liang
No abstract text is available yet for this article.
January 31, 2017: Bioinformatics
Yoriko Lill, Lorne D Jordan, Chuck R Smallwood, Salete M Newton, Markus A Lill, Phillip E Klebba, Ken Ritchie
The important process of nutrient uptake in Escherichia coli, in many cases, involves transit of the nutrient through a class of beta-barrel proteins in the outer membrane known as TonB-dependent transporters (TBDTs) and requires interaction with the inner membrane protein TonB. Here we have imaged the mobility of the ferric enterobactin transporter FepA and TonB by tracking them in the membranes of live E. coli with single-molecule resolution at time-scales ranging from milliseconds to seconds. We employed simple simulations to model/analyze the lateral diffusion in the membranes of E...
2016: PloS One
Konstantinos D Tsirigos, Arne Elofsson, Pantelis G Bagos
MOTIVATION: The PRED-TMBB method is based on Hidden Markov Models and is capable of predicting the topology of beta-barrel outer membrane proteins and discriminate them from water-soluble ones. Here, we present an updated version of the method, PRED-TMBB2, with several newly developed features that improve its performance. The inclusion of a properly defined end state allows for better modeling of the beta-barrel domain, while different emission probabilities for the adjacent residues in strands are used to incorporate knowledge concerning the asymmetric amino acid distribution occurring there...
September 1, 2016: Bioinformatics
Martin Bommer, Ana-Nicoleta Bondar, Athina Zouni, Holger Dobbek, Holger Dau
In all organisms that employ oxygenic photosynthesis, the membrane-extrinsic PsbO protein is a functionally important component of photosystem II. To study the previously proposed proton antenna function of carboxylate clusters at the protein-water interface, we combined crystallography and simulations of a truncated cyanobacterial (Thermosynechococcus elongatus) PsbO without peripheral loops. We expressed the PsbO β-barrel heterologously and determined crystal structures at resolutions of 1.15-1.5 Å at 100 K at various pH values and at 297 K and pH 6...
August 23, 2016: Biochemistry
Leonie van 't Hag, Hsin-Hui Shen, Tsung-Wu Lin, Sally L Gras, Calum J Drummond, Charlotte E Conn
A fundamental understanding of the effect of amphiphilic protein encapsulation on the nanostructure of the bicontinuous cubic phase is crucial to progressing biomedical and biological applications of these hybrid protein-lipid materials, including as drug delivery vehicles, as biosensors, biofuel cells and for in meso crystallization. The relationship between the lipid nanomaterial and the encapsulated protein, however, remains poorly understood. In this study, we investigated the effect of incorporating the five transmembrane and lipo-proteins which make up the β-barrel assembly machinery from Gram-negative bacteria within a series of bicontinuous cubic phases...
November 29, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Anand Kumar Rai, Kausik Chattopadhyay
Vibrio cholerae cytolysin (VCC) is a membrane-damaging beta-barrel pore-forming toxin (beta-PFT). VCC causes permeabilization of the target membranes by forming transmembrane oligomeric beta-barrel pores. Oligomerization is a key step in the mode of action of any beta-PFT, including that of VCC. Earlier studies have identified some of the key residues in VCC that are directly involved in the generation of the inter-protomer contacts, thus playing critical roles in the oligomerization of the membrane-bound toxin...
June 3, 2016: Biochemical and Biophysical Research Communications
Andrea Magrì, Maria Carmela Di Rosa, Marianna Flora Tomasello, Francesca Guarino, Simona Reina, Angela Messina, Vito De Pinto
Cu/Zn Superoxide Dismutase (SOD1), the most important antioxidant defense against ROS in eukaryotic cells, localizes in cytosol and intermembrane space of mitochondria (IMS). Several evidences show a SOD1 intersection with both fermentative and respiratory metabolism. The Voltage Dependent Anion Channel (VDAC) is the main pore-forming protein in the mitochondrial outer membrane (MOM), and is considered the gatekeeper of mitochondrial metabolism. Saccharomyces cerevisiae lacking VDAC1 (Δpor1) is a very convenient model system, since it shows an impaired growth rate on non-fermentable carbon source...
June 2016: Biochimica et Biophysica Acta
Wangfei Wang, Constance J Jeffery
Proteins expressed on the bacterial cell surface play important roles in infection and virulence and can be targets for vaccine development or used as biomarkers. Surprisingly, an increasing number of surface proteins are being found to be identical to intracellular enzymes and chaperones, and a few dozen intracellular/surface moonlighting proteins have been found that have different functions inside the cell and on the cell surface. The results of twenty-two published bacterial surface proteomics studies were analyzed using bioinformatics tools to consider how many additional intracellular proteins are also found on the cell surface...
April 26, 2016: Molecular BioSystems
Maria A Schumacher, Wenjie Zeng, Kuo-Hsiang Huang, Lukasz Tchorzewski, Anuradha Janakiraman
In Escherichia coli cell division is driven by the tubulin-like GTPase, FtsZ, which forms the cytokinetic Z-ring. The Z-ring serves as a dynamic platform for the assembly of the multiprotein divisome, which catalyzes membrane cleavage to create equal daughter cells. Several proteins effect FtsZ assembly, thereby providing spatiotemporal control over cell division. One important class of FtsZ interacting/regulatory proteins is the Z-ring-associated proteins, Zaps, which typically modulate Z-ring formation by increasing lateral interactions between FtsZ protofilaments...
January 29, 2016: Journal of Biological Chemistry
Lavinia Liguori, Barry Stidder, Jean-Pierre Alcaraz, Jean-Luc Lenormand, Philippe Cinquin, Donald K Martin
The mitochondrial voltage-dependent anion channel (VDAC) is a pivotal protein since it provides the major transport pathway between the cytosol and the mitochondrial intermembrane space and it is implicated in cell apoptosis by functioning as a gatekeeper for the trafficking of mitochondrial death molecules. VDAC is a beta-barrel channel with a large conductance, and we use it as a model transport protein for the design of biomimetic systems. To overcome the limitations of classical overexpression methods for producing and purifying membrane proteins (MPs) we describe here the use of an optimized cell-free system...
August 17, 2016: Preparative Biochemistry & Biotechnology
Thomas Ulrich, Philipp Oberhettinger, Ingo B Autenrieth, Doron Rapaport
Beta-barrel proteins are found in the outer membrane of Gram-negative bacteria, mitochondria, and chloroplasts. The evolutionary conservation in the biogenesis of these proteins allows mitochondria to assemble bacterial β-barrel proteins in their functional form. In this chapter, we describe exemplarily how the capacity of yeast mitochondria to process the trimeric autotransporter YadA can be used to study the role of bacterial periplasmic chaperones in this process.
2015: Methods in Molecular Biology
Anna Konovalova, Thomas J Silhavy
Bacterial lipoproteins are lipid-anchored proteins that contain acyl groups covalently attached to the N-terminal cysteine residue of the mature protein. Lipoproteins are synthesized in precursor form with an N-terminal signal sequence (SS) that targets translocation across the cytoplasmic or inner membrane (IM). Lipid modification and SS processing take place at the periplasmic face of the IM. Outer membrane (OM) lipoproteins take the localization of lipoproteins (Lol) export pathway, which ends with the insertion of the N-terminal lipid moiety into the inner leaflet of the OM...
October 5, 2015: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
Karen G Fleming
In vitro folding studies of outer membrane beta-barrels have been invaluable in revealing the lipid effects on folding rates and efficiencies as well as folding free energies. Here, the biophysical results are summarized, and these kinetic and thermodynamic findings are considered in terms of the requirements for folding in the context of the cellular environment. Because the periplasm lacks an external energy source the only driving forces for sorting and folding available within this compartment are binding or folding free energies and their associated rates...
October 5, 2015: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
Barkha Khilwani, Kausik Chattopadhyay
Pore-forming toxins (PFTs) are a distinct class of membrane-damaging cytolytic proteins that contribute significantly towards the virulence processes employed by various pathogenic bacteria. Vibrio cholerae cytolysin (VCC) is a prominent member of the beta-barrel PFT (beta-PFT) family. It is secreted by most of the pathogenic strains of the intestinal pathogen V. cholerae. Owing to its potent membrane-damaging cell-killing activity, VCC is believed to play critical roles in V. cholerae pathogenesis, particularly in those strains that lack the cholera toxin...
August 2015: Toxins
Anand Kumar Rai, Nidhi Kundu, Kausik Chattopadhyay
Vibrio cholerae cytolysin (VCC) is a potent membrane-damaging cytotoxic protein. VCC causes permeabilization of the target cell membranes by forming transmembrane oligomeric beta-barrel pores. Membrane pore formation by VCC involves following key steps: (i) membrane binding, (ii) formation of a pre-pore oligomeric intermediate, (iii) membrane insertion of the pore-forming motifs, and (iv) formation of the functional transmembrane pore. Membrane binding, oligomerization, and subsequent pore-formation process of VCC appear to be facilitated by multiple regulatory mechanisms that are only partly understood...
October 1, 2015: Archives of Biochemistry and Biophysics
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"