Source:
Generated By: https://synbiohub.org/public/igem/igem2sbol/1
Created by: Marthe J??rgensen
Date created: 2016-09-22 11:00:00
Date modified: 2016-10-14 01:24:20
Beta-lacatamase enzyme called blaNDM-1
| Types | DnaRegion |
| Roles | CDS Coding |
| Sequences | BBa_K1927000_sequence (Version 1) |
Description
Usage and biology:During the last decade antibiotic resistance has grown not only in incidents but also in
awareness among the public. Rapid detection of these incidents is essential in the battle
against sophisticated bacteria. Beta lactamases are enzymes that provides one of the many
mechanisms of antibiotic resistance. Its for this reason regulary used among researchers as
a selection marker. Bacteria that has been subjected to a procedure where foreign DNA is
introduced, an antibiotic resistance gene is often use to check if colonies succsesfully has
taken up the DNA and expressed it.
An example of this is ampicillin which is a highly used selection marker. The need for a
selection marker in genetical engineering has been shown extremly usefull. By transforming
a bacteria with a particular gene plus an antibiotic resistance gene it allows the researcher to
know exactly which colonies that has taken up the DNA. By plating them out on agar plates
with a given antibiotic, only the bacteria with the resistance gene can grow. Cells that did not
manage to take up the DNA will die.
The mechanism of beta lactamases are oriented to the bacterial cell wall. This cell wall is
unique to bacteria and consist of several components. Gram Positive and gram negative
bacteria will have a different cell wall composition.
In general, Gram??positive bacteria have a thicker layer of cell wall as well as a layer of
cytoplasmic membrane. These layers consist of several conserved compounds such as
monomeric disaccharide tetrapeptide, which are usually also those that will trigger an
immunological defence respons of the host.
Gram??negative bacteria (e.g., Escherichia coli) typically contain an outer membrane, an
intervening periplasmic space where a thin layer of cell wall resides, and a layer of
cytoplasmic membrane.
Beta lactamases are usually produced both by gram negative and positive bacteria, either
from plasmid or chromosomally. Beta lactamases are able to resist several types of
antibiotics. These antibiotics all have in common a 4 ?? atom ring called beta lactam ring
which the enzyme are able to hydrolyze and break open and the molecule looses its
antibacterial function.
Penicillin, a regulary used antibiotic have such a beta lactam ring.
This drug was the first antibiotic to be discovered and is still widely used today. This ring will
bind to an enzyme (DD ???transpeptidase) that is in charge of renewing the bacterial cell wall.
Without this enzyme there will be no new formations of peptidoglycans for the cell wall and
the integrity of the bacterial cell wall will be lost, it will eventually rupture and the bacteria will
die. By hydrolyzing the ring, it will make the molecule unable to bind to the cell wall
producing enzyme, thus the Penicillin have lost its destructive activity.