Disulfide bond of Mycoplasma pneumoniae community-acquired respiratory distress syndrome toxin is essential to maintain the ADP-ribosylating and vacuolating activities.

Abstract

Mycoplasma pneumoniae is the leading cause of bacterial community-acquired pneumonia among hospitalised children in United States and worldwide. Community-acquired respiratory distress syndrome (CARDS) toxin is a key virulence determinant of M. pneumoniae. The N-terminus of CARDS toxin exhibits ADP-ribosyltransferase (ADPRT) activity, and the C-terminus possesses binding and vacuolating activities. Thiol-trapping experiments of wild-type (WT) and cysteine-to-serine-mutated CARDS toxins with alkylating agents identified disulfide bond formation at the amino terminal cysteine residues C230 and C247. Compared with WT and other mutant toxins, C247S was unstable and unusable for comparative studies. Although there were no significant variations in binding, entry, and retrograde trafficking patterns of WT and mutated toxins, C230S did not elicit vacuole formation in intoxicated cells. In addition, the ADPRT domain of C230S was more sensitive to all tested proteases when compared with WT toxin. Despite its in vitro ADPRT activity, the reduction of C230S CARDS toxin-mediated ADPRT activity-associated IL-1β production in U937 cells and the recovery of vacuolating activity in the protease-released carboxy region of C230S indicated that the disulfide bond was essential not only to maintain the conformational stability of CARDS toxin but also to properly execute its cytopathic effects.

• Authors: Sowmya Balasubramanian, Lavanya Pandranki, Suzanna Maupin, Kumaraguruparan Ramasamy, Alexander B Taylor, Peter John Hart, Joel B Baseman, Thirumalai R Kannan
• Journal: Cellular microbiology (Cell Microbiol) Vol. 21 Issue 8 Pg. e13032 (08 2019) ISSN: 1462-5822 [Electronic] India
• PMID: 30977272 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: © 2019 John Wiley & Sons Ltd.

Chemical References

• Bacterial Proteins
• Bacterial Toxins
• CARDS toxin, Mycoplasma pneumoniae
• Disulfides
• IL1B protein, human
• Interleukin-1beta
• Recombinant Proteins

Topics

• ADP-Ribosylation
• Animals
• Bacterial Proteins (chemistry, genetics, metabolism)
• Bacterial Toxins (chemistry, genetics, metabolism)
• Binding Sites
• CHO Cells
• Cell Line, Tumor
• Cricetulus
• Disulfides (chemistry, metabolism)
• Escherichia coli (genetics, metabolism)
• Gene Expression
• HeLa Cells
• Host-Pathogen Interactions (genetics)
• Humans
• Interleukin-1beta (biosynthesis)
• Macrophages (microbiology, pathology)
• Models, Molecular
• Mutation
• Mycoplasma pneumoniae (genetics, metabolism, pathogenicity)
• Protein Binding
• Protein Conformation, alpha-Helical
• Protein Conformation, beta-Strand
• Protein Interaction Domains and Motifs
• Protein Structure, Tertiary
• Recombinant Proteins (chemistry, genetics, metabolism)
• Structure-Activity Relationship
• Vacuoles (metabolism, microbiology, ultrastructure)
• Virulence