Initial Kinetic Characterization of Sterile Alpha and Toll/Interleukin Receptor Motif-Containing Protein 1

Heather S. Loring, Janneke D. Icso, Venkatesh V. Nemmara, Paul R. Thompson

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Sterile alpha and toll/interleukin receptor (TIR) motif-containing protein 1 (SARM1) plays a pivotal role in triggering the neurodegenerative processes that underlie peripheral neuropathies, traumatic brain injury, and neurodegenerative diseases. Importantly, SARM1 knockdown or knockout prevents degeneration, thereby demonstrating that SARM1 is a promising therapeutic target. Recently, SARM1 was shown to promote neurodegeneration via its ability to hydrolyze NAD+, forming nicotinamide and ADP ribose (ADPR). Herein, we describe the initial kinetic characterization of full-length SARM1, as well as the truncated constructs corresponding to the SAM1-2TIR and TIR domains, highlighting the distinct challenges that have complicated efforts to characterize this enzyme. Moreover, we show that bacterially expressed full-length SARM1 (kcat/KM = 6000 ± 2000 M-1 s-1) is at least as active as the TIR domain alone (kcat/KM = 1500 ± 300 M-1 s-1). Finally, we show that the SARM1 hydrolyzes NAD+ via an ordered uni-bi reaction in which nicotinamide is released prior to ADPR.

Original languageEnglish (US)
Pages (from-to)933-942
Number of pages10
JournalBiochemistry
Volume59
Issue number8
DOIs
StatePublished - Mar 3 2020
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biochemistry

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