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Updated: Apr 9, 2026
Purification of a High Molecular Mass Protein in Streptococcus mutans
Published on: September 14, 2019
Functional and Structural Characterization of the Antiphagocytic Properties of a Novel Transglutaminase from
Jie Yu1, Yaya Pian1, Jingpeng Ge2
1From the State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China, Key Laboratory for Protein Sciences of Ministry of Education, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China, and.
Abstract:
Streptococcus suis serotype 2 (Ss2) is an important swine and human zoonotic pathogen. In the present study, we identified a novel secreted immunogenic protein, SsTGase, containing a highly conserved eukaryotic-like transglutaminase (TGase) domain at the N terminus. We found that inactivation of SsTGase significantly reduced the virulence of Ss2 in a pig infection model and impaired its antiphagocytosis in human blood. We further solved the crystal structure of the N-terminal portion of the protein in homodimer form at 2.1 Å. Structure-based mutagenesis and biochemical studies suggested that disruption of the homodimer directly resulted in the loss of its TGase activity and antiphagocytic ability. Characterization of SsTGase as a novel virulence factor of Ss2 by acting as a TGase would be beneficial for developing new therapeutic agents against Ss2 infections.
