Abstract:
:Listeriolysin O (LLO) is a cholesterol-dependent cytolysin that is an essential virulence factor of Listeria monocytogenes. LLO pore-forming activity is pH-dependent; it is active at acidic pH (<6), but not at neutral pH. In contrast to other pH-dependent toxins, we have determined that LLO pore-forming activity is controlled by a rapid and irreversible denaturation of its structure at neutral pH at temperatures >30 degrees C. Rapid denaturation is triggered at neutral pH by the premature unfolding of the domain 3 transmembrane beta-hairpins; structures that normally form the transmembrane beta-barrel. A triad of acidic residues within domain 3 function as the pH sensor and initiate the denaturation of LLO by destabilizing the structure of domain 3. These studies provide a view of a molecular mechanism by which the activity of a bacterial toxin is regulated by pH.
journal_name
Proc Natl Acad Sci U S Aauthors
Schuerch DW,Wilson-Kubalek EM,Tweten RKdoi
10.1073/pnas.0500558102keywords:
subject
Has Abstractpub_date
2005-08-30 00:00:00pages
12537-42issue
35eissn
0027-8424issn
1091-6490pii
0500558102journal_volume
102pub_type
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