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Updated: Jun 21, 2026
An In Vitro Assay to Detect tRNA-Isopentenyl Transferase Activity
Published on: October 8, 2018
Characterization of a unique ADP-ribosyltransferase of Mycoplasma penetrans
Coreen Johnson1, T R Kannan, Joel B Baseman
1Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, MC 7758, San Antonio, TX 78229-3900, USA.
Abstract:
Mycoplasma penetrans is a urogenital tract pathogen implicated in the deterioration of the immune system in human immunodeficiency virus-infected AIDS patients. Here, we describe a 78-kDa protein from M. penetrans, designated MYPE9110, that exhibits sequence similarity to known ADP-ribosyltransferases (ADPRTs) such as Bordetella pertussis pertussis toxin and Mycoplasma pneumoniae community-acquired respiratory distress syndrome toxin. MYPE9110 possesses key amino acid residues found in all ADPRTs that are essential for ADPRT activity. Several mammalian cell proteins are ADP-ribosylated by MYPE9110, and the full-length recombinant protein exhibits a strong auto-ADP-ribosylating activity. In the absence of target proteins, MYPE9110 demonstrates a NAD-glycohydrolase activity by hydrolyzing NAD. Furthermore, this toxin elicits cytopathology in HeLa cells by inducing cytoplasmic vacuolization in the presence of ammonium chloride. The deletion of the C-terminal region of MYPE9110 significantly diminishes its binding to host cells while still exhibiting an ADPRT activity, suggesting that MYPE9110 is a member of the family of A-B ADPRT toxins.
Insights
Mycoplasma penetrans harbors a novel toxin, MYPE9110, that damages host cells by ADP-ribosylation and NAD hydrolysis. This protein contributes to immune system decline in AIDS patients.
Area of Science:
- Microbiology
- Molecular Biology
- Immunology
Background:
- Mycoplasma penetrans is a urogenital pathogen linked to immune deterioration in AIDS patients.
- ADP-ribosyltransferases (ADPRTs) are toxins that modify host proteins, impacting cellular functions.
Purpose of the Study:
- To characterize a novel 78-kDa protein, MYPE9110, from M. penetrans.
- To investigate the enzymatic activities and cellular effects of MYPE9110.
Main Methods:
- Sequence analysis to identify conserved ADPRT motifs.
- In vitro assays to assess ADP-ribosylation and NAD-glycohydrolase activities.
- Cell-based assays using HeLa cells to observe cytopathology and protein binding.
Main Results:
- MYPE9110 shares sequence similarity with known bacterial ADPRTs and possesses essential catalytic residues.
- The protein ADP-ribosylates mammalian proteins and exhibits auto-ADP-ribosylation and NAD-glycohydrolase activity.
- MYPE9110 induces cytoplasmic vacuolization in HeLa cells; C-terminal deletion affects host cell binding but not enzymatic activity.
Conclusions:
- MYPE9110 is a novel A-B ADPRT toxin from Mycoplasma penetrans.
- This toxin contributes to the pathogenesis of M. penetrans, potentially exacerbating immune decline in HIV-infected individuals.
- MYPE9110 represents a new target for understanding and potentially counteracting Mycoplasma-associated diseases.
