It’s a well-known fact that antibiotics are used to inhibit the development of bacteria and also to treat bacteria-related diseases.
But have you pondered why some of the time you take antibiotics and it doesn’t appear to be performing the work it was aiming for or have you heard about antibiotic resistance and you keep wondering what it is all about?
Well, I would have you know that bacteria also knows how to shield itself from its adversary, which is antibiotics.
Bacteria have an external film made up of proteins, which serves as a barrier to prevent harmful chemicals like antibiotics from entering and destroying it. This protein is known as porin.
A defining characteristic of Gram-negative bacteria is the presence of an external layer, which functions as an extra boundary, hindering the penetration of poisonous chemicals, such as antimicrobials.
Porins are external membrane proteins associated with the modulation of cellular penetrability and antibiotic resistance.
In this article, we are going to discuss further what porins are, their functions, characteristics and lots more as we progress.
What are porins?
What Are Porins? Porins are proteins that form pores in membranes and they are capable of the transportation of different substances and particles across the layer.
Porins are beta-barrel proteins that cross a cellular membrane and act as a pore through which atoms can diffuse.
Unlike other membrane transport proteins, porins are expansive enough to permit passive diffusion, meaning they act as channels that are particular to distinctive sorts of molecules.
They are present within the external layer of Gram-negative bacteria, some Gram-positive mycobacteria,the mitochondria, and the chloroplast.
Porins are able to specifically control the exchange of anions, cations and other solutes over the bacterial film by acting as pores.
Discovery of Porins
Porins were discovered in the 1970s in Escherichia coli; these proteins are a general feature of the Gram-negative external membrane.
Much of the early work on porins came from the research facilities of Hiroshi Nikaido and Robert Hancock. A few of the microscopic organisms known to have porins are Pseudomonas aeruginosa, many other species of Pseudomonas, Aeromonas salmonicida, Treponema pallidum, and Helicobacter pylori.
Characteristics and Importance of Porins
A porin protein partners with two other porin proteins of the same sort within the outer membrane. This may act to stabilize the three-dimensional structure of each porin particle. Each porin contains a pore so there are three pores within the group of three porins.
Porins have significance within the antibiotic resistance of bacteria, especially Pseudomonas aeruginosa, which is the cause of lung diseases in those afflicted with cystic fibrosis and can cause so-called “opportunistic infections” in those whose immune system is impeded.
Another illustration of porin significance is found in Escherichia coli. In this bacterium, a team of porins, which are assigned OmpF and OmpC, work in reaction to changes in osmolarity.
The generation of these porins is beneath the control of a protein that senses the osmotic character of the environment. Depending on the ionic conditions, the sums of OmpF and OmpC within the external membrane can be modified to control the types of ions that enter the bacterium.
A bacterium ordinarily contains a variety of porins. Possession of porins of diverse sizes and chemistries is exceptionally invaluable for a bacterium.
The different channels permit the inward diffusion of a variety of nutrients required by the bacterium for survival and development.
In addition, the diffusional nature of the molecule’s passage implies that a bacterium can secure a few required nutrients without having to use energy.
Porins take part in different physiological processes, including the uptake of small molecules for development and cell work, inflammation and immune response of the host, and cell-to-cell contacts.
Structure of Porins
Porins are composed of beta sheets (β sheets) made up of beta strands (β strands), which are connected together by beta turns (β turns) on the cytoplasmic side and long circles of amino acids on the other. The β strands lie in an antiparallel design and frame a round and hollow tube called a beta barrel (β barrel)
The beta-barrel is normally made up of 300 to 400 amino acids, which are regularly shaped around 16 anti-parallel beta strands, which are tilted at 45-degree angles. Each beta strand comprises an arrangement of alternating polar and non-polar amino acids.
Antibiotic Resistance
Antibiotic resistance does not mean our body is resistant to antimicrobials. It simply means the microbes causing the disease are resistant to the antimicrobial treatment.
Antimicrobial resistance happens when germs, like microscopic organisms, create the capacity to overcome the drugs planned to murder them.
Resistant diseases can be troublesome and, sometimes, impossible to treat. Antimicrobial resistance may be a normally occurring process.
In any case, increments in antimicrobial resistance are driven by a combination of germs exposed to antimicrobials and the spread of those germs and their resistance components.
Porins and Antibiotic Resistance
The cell membranes of gram-negative bacteria are pivotal for their survival and natural adaptation. For the most part, these membranes not only allow gram-negative bacteria surface specificity but also work as a useful and defensive barrier for them.
Gram-negative bacteria have twofold layers that incorporate an outer membrane (OM) made up of outer membrane proteins (Omps) and other components
In a few circumstances, poisonous substances, such as antibiotics, are prevented from transiting through the OM, making an impressive impediment to the annihilation of gram-negative diseases with conventional or novel antimicrobial agents.
Porins make tiny channels within the membrane and allow passive transport of hydrophilic compounds, which makes a difference in balancing cellular permeability and increasing antibiotic resistance.
Gram-negative Bacteria
Gram-negative microscopic organisms are the genus of the bacteria family and a part of the phylum Firmicutes. They are a bunch of oxygen-consuming microscopic organisms that do not hold the crystal violet dye during the procedure of Gram staining and show up pink in color when inspected beneath the microscope.
According to the NIH (National Institute of Health), gram-negative bacteria (GNB) are among the world’s most critical public health issues due to their high resistance to antimicrobials.
These microorganisms have noteworthy clinical significance in clinics since they put patients within the intensive care unit (ICU) at high risk and lead to high morbidity and mortality.
Two expansive groups, Enterobacteriaceae and the non-fermenters, are responsible for most clinical isolates; in any case, other clinically concerning gram-negative organisms exist, including but not limited to Neisseria, Haemophilus spp., Helicobacter pylori, and Chlamydia trachomatis.
Final Words
Porins play an essential role in the protection of bacteria, mostly gram-negative bacteria, from toxins like antibiotics.
Porins are proteins found on the outer membrane of a bacteria cell, preventing it from getting killed by forming a barrier to become antibiotic resistant. It also helps in nutrient exchange and pathogenesis.
