Difference between revisions of "Part:BBa K177026"
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Listeriolysin O (LLO) is a pore-forming protein from Listeria monocytogenes which belong to hemolysin family. The toxin may be considered a virulence factor, since because of its pivotal role for the virulence of ''L. monocytogenes''. | Listeriolysin O (LLO) is a pore-forming protein from Listeria monocytogenes which belong to hemolysin family. The toxin may be considered a virulence factor, since because of its pivotal role for the virulence of ''L. monocytogenes''. | ||
| − | + | [[Image:PERFRINGOLYSIN.png|thumb|left|450px|Crystal structure of perfringolysin which is close related to lysteriolysin O]] | |
Listeriolysin O is a thiol-activated cholesterol-dependent pore forming toxin protein - it is activated by reducing agents and inhibited by oxidizing agents. However, LLO differs from other thiol-activated toxins, since its cytolytic activity is maximized at a pH of 5.5, which occur in the phagosome | Listeriolysin O is a thiol-activated cholesterol-dependent pore forming toxin protein - it is activated by reducing agents and inhibited by oxidizing agents. However, LLO differs from other thiol-activated toxins, since its cytolytic activity is maximized at a pH of 5.5, which occur in the phagosome | ||
It cause that LLO is selectively activated within the acidic phagosomes of cells that have phagocytosed L. monocytogenes. After LLO lyses the phagosome, the bacterium escapes into the cytosol, where it can grow intracellularly. Upon release from the phagosome, activity of the protein is reduced due to more basic environment. | It cause that LLO is selectively activated within the acidic phagosomes of cells that have phagocytosed L. monocytogenes. After LLO lyses the phagosome, the bacterium escapes into the cytosol, where it can grow intracellularly. Upon release from the phagosome, activity of the protein is reduced due to more basic environment. | ||
Revision as of 09:53, 20 October 2009
listeriolysin O 399G->C - locus from Listeria monocytogenes
Listeriolysin O (LLO) is a pore-forming protein from Listeria monocytogenes which belong to hemolysin family. The toxin may be considered a virulence factor, since because of its pivotal role for the virulence of L. monocytogenes.
Listeriolysin O is a thiol-activated cholesterol-dependent pore forming toxin protein - it is activated by reducing agents and inhibited by oxidizing agents. However, LLO differs from other thiol-activated toxins, since its cytolytic activity is maximized at a pH of 5.5, which occur in the phagosome It cause that LLO is selectively activated within the acidic phagosomes of cells that have phagocytosed L. monocytogenes. After LLO lyses the phagosome, the bacterium escapes into the cytosol, where it can grow intracellularly. Upon release from the phagosome, activity of the protein is reduced due to more basic environment.
Aforementioned mechanism permit bacteria to escape from phagosomes into the cytosol without damaging the plasma membrane of the infected cell. This allows the bacteria to live intracellularly, where they are protected from extracellular immune system factors such as the complement system and antibodies.
A PEST-like sequence is present in LLO and is considered essential for virulence, since mutants lacking the sequence lysed the host cell.
Sequence and Features
- 10COMPATIBLE WITH RFC[10]
- 12INCOMPATIBLE WITH RFC[12]Illegal NheI site found at 1380
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE WITH RFC[1000]