Low membrane permeability is commonly acquired due to the decrease in the expression of membrane porins
such as OprD or mutations in the genes encoding it; OprD porin
is imipenem substrate-specific and facilitates the diffusion of basic amino acids and small peptides (3, 9).
The analysis of the outer membrane proteins profile by SDS-PAGE showed that both isolates lost the major porins
OmpK35 and OmpK36.
The outer membrane proteins (OMPs), called porins
, are characterized by a [beta]-barrel structure and form water-filled channels for the passage of a large variety of hydrophilic molecules [7-9].
[sup], In recent studies, the clinical isolates of this species has not only shown the extended-spectrum [sz]-lactamase TEM-24, which results in resistance to [sz]-lactam antibiotics, [sup],, but also resistance to quinolones, tetracycline, and chloramphenicol, due to reduced drug uptake, by losing porins
on the outer membrane.
Creative Biolabs has successfully expressed different types of membrane proteins such as GPCRs, ion channels, porins
, viral proteins, transporters, drug receptors, etc.
In order to get inside the cell, these molecules must pass through porins
, which are protein channels that span the outer membrane.
To the Editor: Class 2 and class 3 porin
(PorB) proteins are the major proteins found in the outer membrane of Neisseria meningitidis (1); they function as porins
, allowing the passage of small molecules through the outer membrane.
[2,3] This is accomplished by mutations of genes encoding the outer-membrane protein channels called porins
.  Because the transport systems are essential to bacterial viability, this mechanism of resistance is weak, and may sometimes be overcome by increasing the antibiotic dose.
These proteins, called porins
, are usually employed by bacteria to form channels that allow nutrients to enter through the cell wall.
AmpC [beta]-lactamase, altered porins
, or both are usually responsible for cefoxitin resistance in Escherichia coil We examined the relative importance of each.
These omp genes encode porins
that are sometimes flanked by insertion sequences.
Gonococcal resistance to fluoroquinolones is associated with mutations in the genes encoding DNA gyrase (gyrA) and topoisomerase (parC) as well as change in porin
permeability and reduced intracellular drug accumulation (6).