8G83

Structure of NAD+ consuming protein Acinetobacter baumannii TIR domain

Summary for 8G83

• Entry DOI: 10.2210/pdb8g83/pdb
• Related: 7UWG 7UXU
• Descriptor: NAD(+) hydrolase AbTIR (2 entities in total)
• Functional Keywords: nadase, bacterial tir, hydrolase, cadpr
• Biological source: Acinetobacter baumannii 1295743
• Total number of polymer chains: 2
• Total formula weight: 40835.21

Authors

Klontz, E.H.,Wang, Y.,Glendening, G.,Carr, J.,Tsibouris, T.,Buddula, S.,Nallar, S.,Soares, A.,Snyder, G.A. (deposition date: 2023-02-17, release date: 2023-10-11, Last modification date: 2023-11-15)

Primary citation

Klontz, E.,Obi, J.O.,Wang, Y.,Glendening, G.,Carr, J.,Tsibouris, C.,Buddula, S.,Nallar, S.,Soares, A.S.,Beckett, D.,Redzic, J.S.,Eisenmesser, E.,Palm, C.,Schmidt, K.,Scudder, A.H.,Obiorah, T.,Essuman, K.,Milbrandt, J.,Diantonio, A.,Ray, K.,Snyder, M.L.D.,Deredge, D.,Snyder, G.A.
The structure of NAD + consuming protein Acinetobacter baumannii TIR domain shows unique kinetics and conformations.
J.Biol.Chem., 299:105290-105290, 2023

PubMed Abstract: Toll-like and interleukin-1/18 receptor/resistance (TIR) domain-containing proteins function as important signaling and immune regulatory molecules. TIR domain-containing proteins identified in eukaryotic and prokaryotic species also exhibit NAD+ hydrolase activity in select bacteria, plants, and mammalian cells. We report the crystal structure of the Acinetobacter baumannii TIR domain protein (AbTir-TIR) with confirmed NAD hydrolysis and map the conformational effects of its interaction with NAD using hydrogen-deuterium exchange-mass spectrometry. NAD results in mild decreases in deuterium uptake at the dimeric interface. In addition, AbTir-TIR exhibits EX1 kinetics indicative of large cooperative conformational changes, which are slowed down upon substrate binding. Additionally, we have developed label-free imaging using the minimally invasive spectroscopic method 2-photon excitation with fluorescence lifetime imaging, which shows differences in bacteria expressing native and mutant NAD+ hydrolase-inactivated AbTir-TIR protein. Our observations are consistent with substrate-induced conformational changes reported in other TIR model systems with NAD+ hydrolase activity. These studies provide further insight into bacterial TIR protein mechanisms and their varying roles in biology.

PubMed: 37758001
DOI: 10.1016/j.jbc.2023.105290

Experimental method

X-RAY DIFFRACTION (3.03 Å)