Listeriolysin O (LLO, hly-encoded), a major virulence factor secreted by the bacterial pathogen Listeria monocytogenes, is synthesized as a precursor of 529 residues. To impair LLO secretion, the four residues of the predicted signal sequence cleavage site (EA-KD) were deleted and the mutant LLO protein was expressed in a hly-negative derivative of L. monocytogenes. Unexpectedly, the mutant protein was secreted in normal amounts in the culture supernatant and was fully haemolytic. N-terminal sequencing of the secreted LLO molecule revealed that N-terminal processing of the preprotein occurred three residues downstream of the natural cleavage site. L. monocytogenes expressing this truncated LLO showed a reduced capacity to disrupt the phagosomal membranes of bone marrow macrophages and of hepatocytes; and the mutant strain showed a 100-fold decrease in virulence in the mouse model. These results suggest that the first N-terminal residues of mature LLO participate directly in phagosomal escape and bacterial infection.
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http://dx.doi.org/10.1099/mic.0.26072-0 | DOI Listing |
Talanta
January 2025
College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30, Puzhu South Road, Nanjing, 211816, China; State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, No. 30, Puzhu South Road, Nanjing, 211816, China. Electronic address:
Enzyme immobilization techniques are crucial for enhancing enzyme stability and catalytic efficiency. Traditional methods such as physical adsorption and simple covalent binding often fail to maintain enzyme activity and stability. In this study, an innovative multi-level immobilization strategy was proposed to achieve efficient targeted immobilization of nuclease P1 (NP1) by fine-tuning the surface microenvironment.
View Article and Find Full Text PDFInt J Mol Sci
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A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia.
Apurinic/apyrimidinic (AP) sites are endogenous DNA lesions widespread in human cells. Having no nucleobases, they are noncoding and promutagenic. AP site repair is generally initiated through strand incision by AP endonuclease 1 (APE1).
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December 2024
Medicines Discovery Institute, Cardiff University, Cardiff CF10 3AT, UK.
DNA gyrase is a bacterial type IIA topoisomerase that can create temporary double-stranded DNA breaks to regulate DNA topology and an archetypical target of antibiotics. The widely used quinolone class of drugs use a water-metal ion bridge in interacting with the GyrA subunit of DNA gyrase. Zoliflodacin sits in the same pocket as quinolones but interacts with the GyrB subunit and also stabilizes lethal double-stranded DNA breaks.
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Fujian Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, China.
The begomoviral V2 protein is known to be multifunctional, including its interaction with and inhibition of CYP1, a papain-like cysteine protease (PLCP). However, the effect of this interaction on viral pathogenicity remains unclear. Cotton leaf curl Multan virus (CLCuMuV), a typical monopartite begomovirus associated with a betasatellite, is one of the main pathogens responsible for cotton leaf curl disease.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
School of Basic Medical Sciences, Hubei University of Chinese Medicine, Wuhan 430065, PR China; Hubei Shizhen Laboratory, Wuhan 430061, PR China; Key Laboratory of·Traditional, Chinese Medicine Resources and Traditional Chinese Medicine Formulas, Hubei University of Chinese Medicine, Wuhan 430065, PR China. Electronic address:
Klebsiella pneumoniae exhibits extensive glycohydrolase activity in the gut microbiota. However, there are few studies on glucomannanase of Klebsiella pneumoniae. This study cloned and characterized a bifunctional mannanase/glucanase (GH8-3995) of K.
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