TY - JOUR
T1 - The structure of NAD+ consuming protein Acinetobacter baumannii TIR domain shows unique kinetics and conformations
AU - Klontz, Erik
AU - Obi, Juliet O.
AU - Wang, Yajing
AU - Glendening, Gabrielle
AU - Carr, Jahid
AU - Tsibouris, Constantine
AU - Buddula, Sahthi
AU - Nallar, Shreeram
AU - Soares, Alexei S.
AU - Beckett, Dorothy
AU - Redzic, Jasmina S.
AU - Eisenmesser, Elan
AU - Palm, Cheyenne
AU - Schmidt, Katrina
AU - Scudder, Alexis H.
AU - Obiorah, Trinity
AU - Essuman, Kow
AU - Milbrandt, Jeffrey
AU - Diantonio, Aaron
AU - Ray, Krishanu
AU - Snyder, Michelle L.D.
AU - Deredge, Daniel
AU - Snyder, Greg A.
N1 - Publisher Copyright:
© 2023 The Authors
PY - 2023/11
Y1 - 2023/11
N2 - 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-TIRE208A 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.
AB - 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-TIRE208A 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.
KW - bacterial pathogenesis
KW - hydrolase
KW - innate immunity
KW - nicotinamide adenine dinucleotide (NAD)
KW - toll/interleukin-1 receptor (TIR)
UR - http://www.scopus.com/inward/record.url?scp=85175266703&partnerID=8YFLogxK
U2 - 10.1016/j.jbc.2023.105290
DO - 10.1016/j.jbc.2023.105290
M3 - Article
C2 - 37758001
AN - SCOPUS:85175266703
SN - 0021-9258
VL - 299
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 11
M1 - 105290
ER -