151. Crystal structure determination of the armadillo repeat domain of Drosophila SARM1 using MIRAS phasing
- Author
-
Zhenyao Luo, Jeffrey D. Nanson, Xinying Jia, W. Gu, Bostjan Kobe, Thomas Ve, and Clemens Vonrhein
- Subjects
Models, Molecular ,In situ ,Multiple isomorphous replacement ,Protein Conformation ,030303 biophysics ,Biophysics ,Crystal structure ,Crystallography, X-Ray ,Method Communications ,Biochemistry ,law.invention ,03 medical and health sciences ,0302 clinical medicine ,Structural Biology ,law ,Cleave ,Genetics ,Animals ,Drosophila Proteins ,Molecular replacement ,Crystallization ,030304 developmental biology ,Nicotinamide mononucleotide ,Armadillo Domain Proteins ,0303 health sciences ,Activator (genetics) ,Chemistry ,Resolution (electron density) ,Condensed Matter Physics ,Drosophila melanogaster ,Armadillo repeats ,NAD+ kinase ,030217 neurology & neurosurgery - Abstract
We describe the crystal structure determination of the ARM domain of Drosophila SARM1 (dSARM1ARM), which required combination of a number of sources of phase information in order to obtain interpretable electron density maps. SARM1 is a central executioner of the process of axon degeneration, a common feature of the early phase of a range of neurodegenerative diseases. SARM1 is held in the inactive state in healthy axons by its N-terminal auto-inhibitory ARM domain, and is activated to cleave NAD+ upon injury, triggering the subsequent axon degeneration. To characterize the molecular mechanism of SARM1 activation, we sought to determine the crystal structure of the SARM1 ARM domain. Here we describe the recombinant production and crystallization of dSARM1ARM, as well as unconventional process used for structure determination. Crystals were obtained in the presence of NMN, a precursor of NAD+ and a potential activator of SARM1, only after in situ proteolysis of the N-terminal 63 residues. After molecular replacement attempts failed, we determined the crystal structure of dSARM1ARM at 1.65 Å resolution using the MIRAS phasing technique with the program autoSHARP, combining data from the native, SeMet-labelled, and Br-soaked crystals. The structure will further our understanding of the regulation of SARM1.
- Published
- 2021
- Full Text
- View/download PDF