Poster Presentation The 47th Lorne Conference on Protein Structure and Function 2022

NAD+ nucleosidase activity and structure study of PumA and AbTIR (#312)

Sulin Li 1 , Mohammad Kawsar Manik 1 , Thomas Ve 2 , Jeff Nanson 1 , Bostjan Kobe 1
  1. School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, QLD, Australia
  2. Institute for Glycomics, Griffith University, Southport, QLD, Australia

Bacterial Toll/interleukin-1 receptor (TIR) domain-containing proteins have been shown to mediate the pathogenicity and anti-viral activity of bacteria. During bacterial infection, TIR domain-containing proteins may act as virulence factors to inhibit hosts’ immune responses by interfering with Toll-like receptor signalling. Additionally, some bacterial TIR domain-containing proteins possess NAD+ nucleosidase activity, which is not only also related to the virulence of pathogenic bacteria, but also plays an important role in bacterial anti-viral defence. While several bacterial TIR domain-containing proteins have been discovered, their structure and mechanisms of NAD+ nucleosidase activity are still largely unknown 1, 2.

Here we report our studies on two bacterial TIR domain-containing proteins: PumA and AbTIR. Recent studies showed that PumA, which is from multi-drug resistant pathogen Pseudomonas aeruginosa PA7, is essential for PA7 strain’s virulence 3. We determined that PumA also has NAD+ nucleosidase activity. Furthermore, we found that the addition of an inhibitor of PumA NAD+ nucleosidase activity (3-AD) induces the formation of PumA filaments, and appears to trap the protein in an active conformation. Acinetobacter baumannii TIR domain-containing protein (AbTir) is one of the few bacterial proteins that has been reported to produce v-cADPR after NAD+ nucleosidase. We determined the crystal structure of AbTIR TIR domain and also observed AbTIR TIR domain filaments upon incubation with 3-AD. Further structural and functional studies will determine the structures of these filaments and investigate the role these assemblies play in bacterial virulence and anti-viral defence.

  1. Chan, S. L., Low, L. Y., Hsu, S., Li, S., Liu, T., Santelli, E., Le Negrate, G., Reed, J. C., Woods, V. L., and Pascual, J. (2009) Molecular mimicry in innate immunity: crystal structure of a bacterial TIR domain. Journal of Biological Chemistry 284, 21386-21392
  2. Essuman, K., Summers, D. W., Sasaki, Y., Mao, X., Yim, A. K. Y., DiAntonio, A., and Milbrandt, J. (2018) TIR domain proteins are an ancient family of NAD+-consuming enzymes. Current Biology 28, 421-430. e424
  3. Imbert, P. R., Louche, A., Luizet, J. B., Grandjean, T., Bigot, S., Wood, T. E., Gagné, S., Blanco, A., Wunderley, L., and Terradot, L. (2017) A Pseudomonas aeruginosa TIR effector mediates immune evasion by targeting UBAP 1 and TLR adaptors. The EMBO journal 36, 1869-1887