Porin proteins. Medical search. Frequent questions

Molecular dynamics simulations of membranes with embedded proteins and peptides: porin, alamethicin and influenza virus M2. (ox.ac.uk)
Many are small peptides, but some are as big as 20 kDa, so at least these qua-lify as respectable proteins. (asmblog.org)
Dr. Eren's research focuses on understanding the structural and mechanistic aspects of Rev-host protein interactions and finding target regions to inhibit Rev activity using antibodies, synthetic peptides, and aptamers. (nih.gov)

Porins are water-filled pores and channels found in the membranes of bacteria and eukaryotes. (wikipedia.org)
Gram-positive bacteria lack outer membranes, so these porin channels are instead bound to specific lipids within the cell walls. (wikipedia.org)
They reasoned that special proteins must exist that would transport DNA across cell membranes. (scienceblogs.com)
[22] A mitochondrion contains outer and inner membranes composed of phospholipid bilayers and proteins . (wikipedia.org)
Proteins in lipid membranes are one of the fundamental building blocks of biological functionality. (phys.org)
More than half of all proteins interact with membranes. (phys.org)
Biological membranes consist of a phospholipid bilayer and a variety of proteins that accomplish vital biological functions. (phys.org)
Mycobacterial outer membranes: in search of proteins. (mpg.de)
Proteins which are found in membranes including cellular and intracellular membranes. (curehunter.com)
Pore forming proteins are typically the proteins that form channels in membranes. (umass.edu)
It imports hundreds of nucleus-encoded proteins, and diverse metabolites are continuously exchanged across the two chromatophore envelope membranes. (frontiersin.org)
Using electrophysiology on tethered bilayer lipid membranes, we confirmed that the FupA/B fusion protein exhibits pore-forming activity with large ionic conductance, a property shared with both FupA and FupB. (encyclopedia.pub)

Use of a Siderophore Receptor and Porin Proteins-Based Vaccine to Control the Burden of Escherichia coli O157:H7 in Feedlot Cattle. (foodengineeringmag.com)
Gupta DD, Saha S, Chakrabarti MK (2005) Involvement of protein kinase C in the mechanism of action of Escherichia coli heat-stable enterotoxin (STa) in a human colonic carcinoma cell line, COLO-205. (springer.com)
The high-affinity interaction of LF with pore-forming outer-membrane proteins (OMPs) of Gram-negative enterics, including Escherichia coli , is critical for the antimicrobial outcome of LF (Gado et al. (ift.org)
To investigate the mode of action of these proteins, we purified recombinant FupA, FupB and FupA/B proteins expressed in Escherichia coli and incorporated them into mixed lipid bilayers. (encyclopedia.pub)

LbtU, from Legionella pneumophila, a novel TonB-independent siderophore uptake outer membrane protein from a species that lacks TonB, is the founding member of a class of porins that may be involved generally in siderophore-mediated iron acquisition. (nih.gov)
Hom (Helicobacter outer membrane) family of OMPs in H. pylori consists of four members (HomA, B, C and D). In the H. pylori genome jhp 0870 open-reading frame (ORF) that codes for HomB outer membrane protein is associated with many stomach diseases and is a novel co-marker for peptic ulcer disease (PUD) 9 , 10 . (nature.com)
We predict this structure to be a membrane protein. (expasy.org)
A membrane protein is a protein molecule that is attached to, or associated with the membrane of a cell or an organelle. (phys.org)
They correspond to functions allowing opportunistic pathogens to colonise the mucus layers, breach the host barriers and invade the mucosae, which could still be aggravated by decreased host-derived pancreatic zymogen granule membrane protein GP2 in CD patients. (bmj.com)
Outer membrane protein G (OmpG) is an innocuous β-barrel porin while Cytolysin A (ClyA) is an α-helical pore forming toxin. (umass.edu)
We have found that the major outer membrane protein of these organisms, the Neisserial porin PorB, can work as an immune adjuvant due to it recognition by the pattern recognition receptor TOLL-like receptor (TLR) 2. (bu.edu)
I am particularly interested in studying the underlying transportation mechanisms in Outer Membrane protein F that acts as one of the main routes of penetration of antibiotics inside bacteria. (lu.se)

Peculiarities of Thermal Denaturation of OmpF Porin from Yersinia Ruck" by Olga D. Novikova, Dmitry K. Chistyulin et al. (usf.edu)
Using SDS-PAGE, spectroscopic methods and differential scanning calorimetry, a detailed study of thermally induced changes in the spatial structure of OmpF porin from the fish pathogen Yersinia ruckeri (Yr-OmpF) was carried out. (usf.edu)
The data obtained allowed us to conclude unambiguously that changes in the spatial structure of the monomers of Yr-OmpF precede the dissociation of the porin trimer. (usf.edu)

H. pylori attaches and colonizes to the human epithelium using some of their outer membrane proteins (OMPs). (nature.com)
Outer membrane proteins (OMPs) of H. pylori play a crucial role in the host-pathogen interaction, virulence and pathogenesis. (nature.com)
Outer membrane proteins (OMPs) are distinctive features of Gram-negative bacteria. (nature.com)
The interaction of LF with microbial surfaces-OMPs of Gram-negative bacteria in particular-has led to other antimicrobial mechanisms, such as the inhibition of microbial attachment to sub-epithelial matrix proteins and detachment of bacteria from mucosal surfaces. (ift.org)
These outer membrane proteins (OMPs) comprise the five subfamilies FupA, FupB, FslE, FmvA, and FmvB, which share a domain of unknown function (DUF3573) and display specific features that might reflect functional differences. (encyclopedia.pub)

With about 10 000 copies per cell the voltage-dependent anion channels (VDACs) are the most abundant proteins of the mitochondrial outer membrane and are known to be involved in mitochondrial processes such as ATP-, calcium or ROS-transport. (uni-marburg.de)
Voltage-dependent anion channel 1 is the major pore-forming protein of the mitochondrial outer membrane. (bvsalud.org)

The main mechanism of quinolone resistance in Klebsiella (K) pneumoniae is caused by mutation of porin-related proteins and efflux pumps. (uwi.edu)
However, carbapenem resistance may also be mediated by the loss or alteration of porin channels, the expression of efflux pumps, or penicillin-binding protein (PBP) modification. (msdmanuals.com)

The functional properties of this system and its porin-like organization provide information critical for understanding ion permeability through the outer cell surface of S-layer-carrying bacterial species. (unica.it)
Some of the proteins that you have looked at to this point are fully functional as a single amino acid chain (e.g., hemerythrin & Ras). (wustl.edu)
Other proteins are only functional when two or more chains associate to form multimeric structures (e.g. (wustl.edu)
RNA codon misreading [formation of toxic, non functional proteins]. (mindmeister.com)
Strategies for cryo-electron tomography of the mycobacterial cell envelope and its pore proteins and functional studies of porin MspA from Mycobacterium smegmatis. (mpg.de)
Numerous proteins regulating the rearrangement of the cytoskeleton are indicative of the functional and structural dynamics of the presynapse. (mdpi.com)
Mitochondrial porin , also known as the voltage-dependent anion channel (VDAC), is a multi-functional channel protein that shuttles metabolites between the mitochondria and the cytosol and implicated in cellular life and death decisions. (sdbonline.org)
The protein is found to be part of a functional network clearly involved in the outer membrane trafficking. (bvsalud.org)
Functional implications, with respect to the high representativity of this protein in the outer membrane fraction, are discussed considering its possible role in primary functions such as the nutrients uptake and the homeostatic balance. (bvsalud.org)

Porins have threshold sizes of transportable molecules that depend on the type of bacteria and porin. (wikipedia.org)
Porins were first discovered in gram-negative bacteria, but gram-positive bacteria with both types of porins have been found. (wikipedia.org)
They exhibit similar transport functions but have a more limited variety of porins, compared to the distribution found in gram-negative bacteria. (wikipedia.org)
HomB protein contributes to the colonization and persistence of H. pylori , and the presence of homB genes affects the number of bacteria adhering to the host cells. (nature.com)
These proteins are numerous and present in a wide range of Gram-negative bacteria. (tcdb.org)
In the classic Hershey-Chase experiment , a small proportion of the 35 S-labeled proteins of the original phage was associated with the bacteria after infection. (asmblog.org)
When exposed to the E. coli bacteria, the antibodies bind to the siderophore receptors and porins and help prevent iron from entering the E. coli cell, causing it to die. (foodengineeringmag.com)
Moreover, although the abundance of most protein groups reflected that of related bacterial populations, we found a specific independent regulation of bacteria-derived cell envelope proteins. (bmj.com)
Activated lactoferrin (ALF) is a new form of a naturally occurring protein from milk that acts as a powerful deterrent to pathogenic bacteria that may be present on a meat surface. (ift.org)
Pore-forming proteins of Gram-negative bacteria are heat-modifiable proteins, i.e., proteins altering their molecular forms (trimers or monomers), and accordingly, their electrophoretic mobilities depending upon denaturation conditions. (usf.edu)

Unlike other membrane transport proteins, porins are large enough to allow passive diffusion, i.e., they act as channels that are specific to different types of molecules. (wikipedia.org)
Finally, transport proteins play an important role in the maintenance of concentrations of ions. (phys.org)
These transport proteins come in two forms: carrier proteins and channel proteins. (phys.org)
It is freely permeable only to GAS O2, CO2, and H2O and contains, in addition to respiratory chain proteins, numerous transport proteins that control the passage of metabolites such as ATP, ADP, pyruvate, Ca2+, and phosphate. (flashcardmachine.com)
Contain transport Proteins for transportation of metabolites! (flashcardmachine.com)

All porins form homotrimers in the outer membrane, meaning that three identical porin subunits associate together to form a porin super-structure with three channels. (wikipedia.org)
subunits) associate to form a working (active) protein. (wustl.edu)
The FapF protein (430 aas) exporter of amyloid subunits, the fibers of which are key components of their biofilm matrix. (tcdb.org)
Some authors demonstrated the loss of the porin trimeric structure only after unfolding of monomer subunits. (usf.edu)

Conclusions This study provides the first evidence that quantifiable bacterial protein signals are associated with CD, which can have a profound impact on future molecular diagnosis. (bmj.com)
Mark L., Lee W. H., Villoutreix B. O., Proctor D., Blackbourn, D., Spiller B. O. and Blom A. M. (2004) KSHV complement control protein mimics human molecular mechanisms for inhibition of the complement system. (lu.se)

Our work was the first revelation that a "noisy" nanopore sensor could not only discriminate among homologous proteins but could maintain this sensitivity and specificity in a serum sample. (umass.edu)

As observed by low-resolution single-particle analysis, we show that the complex possesses a porin-like structural organization, but is larger than other known porins. (unica.it)
SCOPe: Structural Classification of Proteins - extended. (berkeley.edu)
In the present study, we explored the structural aspect of HomA and HomB proteins using various computational, biophysical and small-angle X-ray scattering (SAXS) techniques. (nature.com)
Our study provides essential structural information of unexplored proteins of the Hom family that can help in a better understanding of H. pylori pathogenesis. (nature.com)
Solid-state NMR (ssNMR) is a versatile technique that can provide high-resolution (sub-angstrom) structural data for integral membrane proteins embedded in native and model membrane environments. (nih.gov)
This review describes the spectroscopic experiments and data analysis methods (including assignment) used to generate high-resolution structural data for membrane proteins. (nih.gov)
Structural proteins are attached to microfilaments in the cytoskeleton which ensures stability of the cell. (phys.org)
Protein separation conditions always pose the risk of denaturation or structural alteration of the LF molecule. (ift.org)
In 2015, she joined the Laboratory of Structural Biology Research and the Protein Expression Laboratory at the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS). (nih.gov)
I am a structural biologist interested in understanding the structure of proteins involved in various biological mechanisms. (lu.se)
Blom A. M. , Kask L. and B. Dahlbäck (2001) Structural requirements for the complement regulatory activities of C4b-binding protein. (lu.se)
Kask L., Hillarp A., Ramesh B., Dahlbäck B., and Blom A. M. (2002) Structural requirements for the intra-cellular subunit polymerization of the complement inhibitor C4b-binding protein. (lu.se)

This has led scientists to experiment with other naturally occurring pore proteins such as Mycobacterium smegmatis porin A (MspA). (scienceblogs.com)
The growth rate of Mycobacterium smegmatis depends on sufficient porin-mediated influx of nutrients. (mpg.de)

However, the techniques are now being applied to large, polytopic membrane proteins including receptors, ion channels, and porins. (nih.gov)
SRP, an acronym for siderophore receptors and porins, is a technology that inhibits E. coli's ability to seek and bind iron, which it needs to sustain growth. (foodengineeringmag.com)
When vaccinated with the SRP, the cow's immune system is stimulated to make antibodies against the siderophore receptors and porins. (foodengineeringmag.com)

During her postdoctoral studies at the University of Massachusetts Medical School (UMASS), she focused on the structure and function of outer membrane proteins, mainly Occ-family of porins from P. aeruginosa , and their role in bacterial pathogenesis and antibiotic resistance. (nih.gov)

Although these proteins are listed as members of the Outer Membrane Pore-forming Protein (OMPP-I) Superfamily , it is not certain that they show sequence similarity in their putative porin domains. (tcdb.org)
Putative two domain porin with N-terminal domain homologous to 9.B.153.3.5 and a C-terminal OmpA/MotB domain. (tcdb.org)
Putative porin of 306 aas and 14 putative TMSs. (tcdb.org)
Putative porin of 315 aas and 12 putative beta strands. (tcdb.org)

Additionally, porins can regulate permeability and prevent lysis by limiting the entry of detergents into the cell. (wikipedia.org)
Mutations that result in alterations of the outer membrane porin proteins of Gram-negative organisms lead to decreased permeability of the drug through the outer membrane so less drug reaches the target enzyme. (cdc.gov)
We hypothesize that these proteins are involved in modulating membrane permeability. (frontiersin.org)

Combining immunopurification and subsequent analytical mass spectrometry, hundreds of proteins, including synaptic vesicle proteins, components of the presynaptic fusion and retrieval machinery, proteins involved in intracellular and extracellular signaling and a large variety of adhesion molecules, were identified. (mdpi.com)

The mechanism of interfering with protein translation operates upon actively dividing cells, so may be less effective in slow-growing populations. (frontiersin.org)
The uptake mechanism is known in some cases to involve porins. (asmblog.org)
These results provide a mechanism by which Drosophila Bcl-2 family proteins can control apoptosis and shed light on a link between Rbf1 and mitochondrial dynamics, in vivo. (sdbonline.org)

Two types of porins exist to transport different materials- general and selective. (wikipedia.org)
Selective porins are smaller than general porins, and have specificities for chemical species. (wikipedia.org)
To solve this problem, the cell membrane contains proteins that are selective for unique, water soluble molecules. (wikibooks.org)
The enzyme target site, porin, and efflux mutations may result from the selective pressure of exposure of the organism to antimicrobial agents during therapy and may cause treatment failure. (cdc.gov)

The characterization by mass spectrometry identified an unknown protein whose structure, predicted by AlphaFold, consists of a 8 strands beta-barrel transmembrane organization typical of porins. (bvsalud.org)

However they are often annotated in the NCBI protein database as the DUF1551 or PF04314 family, alpha-amylase catalytic proteins, members of the Phenol_MetA-deg (MetA-pathway of phenol degradation) superfamily, signal peptide proteins and porins. (tcdb.org)
This family belongs to the Outer Membrane Pore-forming Protein I (OMPP-I) Superfamily . (tcdb.org)

While the structure of many porins have been determined using X-ray crystallography, the alternative method of sequencing protein primary structure may also be used instead. (wikipedia.org)
ssNMR data may be used to annotate and refine existing structures in regions of the protein not fully resolved by crystallography (including ligand-binding sites and mobile solvent accessible loop regions). (nih.gov)

Porins are composed of beta sheets (β sheets) made up of beta strands (β strands) which are linked together by beta turns (β turns) on the cytoplasmic side and long loops of amino acids on the other. (wikipedia.org)
The amino acid composition of the porin β strands are unique in that polar and nonpolar residues alternate along them. (wikipedia.org)
The β barrels that make up a porin are composed of as few as eight β strands to as many as twenty-two β strands. (wikipedia.org)
Depending on the size of the porin, the interior of the protein may either be filled with water, have up to two β strands folded back into the interior, or contain a "stopper" segment composed of β strands. (wikipedia.org)
Strand number (n) is the amount of β strands in the porin, and barrel radius (R) refers to the radius of the opening of the porin. (wikipedia.org)

These antibiotics inhibit protein synthesis. (starhealth.in)
When there is no synthesis of protein, it can lead to irregular cell functioning, and the cells will not be able to replicate, which can lead to cell death. (starhealth.in)
The stroma also contains the ___,____, and ribosomes involved in the synthesis of several chloroplast proteins. (flashcardmachine.com)
For example, alteration of host cell metabolism can provide the increased nucleotides necessary for genome replication or increased free amino acids needed for rapid viral protein synthesis. (estme.org)

When MspA's residues are colored by charge (negatively charged amino acids are shown in red, positively charged in blue and neutral in gray) we can see that the native MspA protein might not let a negatively changed molecule like DNA pass through (see if you can see why). (scienceblogs.com)

There are still some contradictory data on the peculiarities of the conformational changes in the porin structure with temperature. (usf.edu)

Membrane receptor proteins serve as connection between the cell's internal and external environments. (phys.org)

Porins are beta barrel proteins that cross a cellular membrane and act as a pore, through which molecules can diffuse. (wikipedia.org)

Blom, A. M. , Rytkönen, A., Vasquez, P., Dahlbäck, B. and Johnsson, A-B. (2001) A novel interaction between type IV pili of Neisseria gonorrhoeae and complement regulatory protein - C4b-binding protein. (lu.se)

Rev has been reported to interact with many host proteins including importin-ß, histone chaperons (Nap1 and B23), and tubulin through its ARM domain. (nih.gov)

OmpG specifically interacted with target proteins and with a high sensitivity. (umass.edu)
In addition, we found that OmpG could discriminate among eight target proteins, four avidin homologues and four antibody homologues. (umass.edu)

Continuous protein pathways are composed of carrier proteins , channels and pumps . (wikibooks.org)
The transport may be active transport by carrier proteins with an energy source, or it may be facilitated diffusion or passive transport via channels. (wikibooks.org)
Carrier proteins are involved in using the energy released from ATP being broken down to facilitate active transport and ion exchange. (phys.org)

however, some dimeric porins have been discovered, as well as an octameric porin. (wikipedia.org)
Further, biophysical experiments suggested that HomA and HomB are dimeric and most likely the cysteine residues present on surface-exposed loops participate in protein-protein interactions. (nature.com)
In other words, the zipper keeps the protein in a dimeric form, allowing another part of the protein to bind DNA. (wustl.edu)

Several parameters have been used to describe the structure of a porin protein. (wikipedia.org)
These parameters are related via the following formulas: 2 π R = n b 2 cos ⁡ ( α ) {\displaystyle 2\pi R={\frac {nb}{2\cos(\alpha )}}} and, tan ⁡ ( α ) = S a n b {\displaystyle \tan(\alpha )={\frac {Sa}{nb}}} Using these formulas, the structure of a porin can be determined by knowing only a few of the available parameters. (wikipedia.org)
The long funnel-shaped structure and nanofluidic characteristics of the YaxAB nanopore enable the electro-osmotic trapping of diverse folded proteins and high-resolution monitoring of PDIs. (nature.com)
Bacterial toxins can be single proteins or oligomeric protein complexes that are organized with distinct AB structure-function properties. (springer.com)
Unraveling the structure of membrane proteins in situ by transfer function corrected cryo-electron tomography. (mpg.de)
The size of such proteins is way too small to be observed by microscopes so to determine their structure we use X-rays and neutron sources. (lu.se)

Furthermore, chromatophore-localized biosynthetic pathways as well as multiprotein complexes include proteins of dual genetic origin, suggesting that mechanisms evolved that coordinate gene expression levels between chromatophore and nucleus. (frontiersin.org)

Irreversible denaturation of membrane proteins in detergent solutions is similar to unfolding of water-soluble multidomain proteins and represents a complex, multistage process. (usf.edu)

For OmpG we probed its potential to be a nanopore sensor for protein detection and quantification. (umass.edu)
A small high affinity ligand, biotin, was covalently attached to loop 6 of OmpG and used to capture biotin-binding proteins. (umass.edu)

The fluoroquinolone susceptibility profile for each clinical isolate is determined by the number and location of mutational changes in specific enzyme target sites, porin proteins, and efflux mechanisms. (cdc.gov)
She currently studies the underlying mechanisms of viral pathogenesis, viral protein-host protein interactions, and the potential use of humanized scFvs and nanobodies for treatment. (nih.gov)

The inhibition of porin under the control of neuronal Ddc-Gal4 result in short lifespan and in an age-dependent loss in locomotor function, phenotypes that are strongly associated with Drosophila models of Parkinson disease . (sdbonline.org)

Blom A. M . , Berggård K., Webb J. H., Villoutreix B., Lindahl G. and Dahlbäck B. (2000) Human C4b-binding protein has overlapping but not identical binding sites for C4b and streptococcal M-proteins. (lu.se)

Resistance to quinolones occurs through chromosomal mutations in the genes encoding these enzymes and by porin and efflux mutations. (cdc.gov)

The Drosophila retinoblastoma protein, Rbf1, induces a debcl and drp1 -dependent mitochondrial apoptosis. (sdbonline.org)
Both proteins can localize at the mitochondrion , but the way they control apoptosis still remains unclear. (sdbonline.org)

Although the paralogous FupB protein lacks such activity, iron transport capacity and a role in membrane stability were reported for the FupA/B chimera, a protein found in some F. tularensis strains, including the live vaccine strain (LVS). (encyclopedia.pub)

The specific amino acids in the channel determine the specificity of the porin to different molecules. (wikipedia.org)
These specificities are determined by the threshold sizes of the porins, and the amino acid residues lining them. (wikipedia.org)

Other researchers initially observed the dissociation of porin oligomers into the folded monomers. (usf.edu)

With this protein, the pore size is closer to the diameter of DNA. (scienceblogs.com)

The HIV-1 Rev protein is a key regulatory factor that is essential for both early and late phases of viral replication cycles, and therefore represents an important viral target for drug development. (nih.gov)

Moreover, results from electrophysiological assays with membrane-reconstituted SDBC disclosed that it is a nonselective channel that has some peculiar gating properties, but also exhibits behavior typically observed in pore-forming proteins, such as porins and ionic transporters. (unica.it)
However, the limited set of chromatophore-encoded solute transporters appears insufficient for supporting metabolic connectivity or protein import. (frontiersin.org)
Here we show by mass spectrometric analyses of enriched insoluble protein fractions that, unexpectedly, nucleus-encoded transporters are not inserted into the chromatophore inner envelope membrane. (frontiersin.org)

The outer membrane is more permeable to hydrophilic substances, due to the presence of porins. (wikipedia.org)

Porins are primarily involved in passively transporting hydrophilic molecules of various sizes and charges across the membrane. (wikipedia.org)

Could proteins involved in DNA repair/mutagenesis when taken up from the environment play a role in bacterial evolution? (asmblog.org)

Organisms12

Chemicals and Drugs15

Analytical, Diagnostic and Therapeutic Techniques and Equipment2

Phenomena and Processes7

Technology, Industry, Agriculture1

Information Science3

Peptides3

Membranes12

Escherichia4

Membrane protein8

Ompf3

OMPs5

Mitochondrial outer membrane2

Efflux pumps2

Functional9

Bacteria10

Transport proteins5

Subunits4

Molecular2

Homologous proteins1

Structural12

Mycobacterium2

Receptors3

Aeruginosa1

Putative4

Permeability3

Intracellular1

Mechanism3

Selective4

Mass spectrometry1

Superfamily2

Crystallography2

Strands5

Synthesis4

MspA1

Conformational1

Receptor1

Beta barrel1

Pili1

Host proteins1

Target proteins2

Carrier proteins3

Dimeric3

Structure6

Pathways1

Water soluble1

OmpG2

Mechanisms2

Inhibition1

Identical1

Enzymes1

Apoptosis2

Vaccine1

Amino2

Monomers1

Pore size1

Viral1

Transporters3

Substances1

Molecules1

Role in bacterial1