Structural basis for the inhibition of the Bacillus subtilis c-di-AMP cyclase CdaA by the phosphoglucomutase GlmM

DOI: 10.1016/j.jbc.2021.101317

Authors: Monisha Pathania (Imperial College London) , Tommaso Tosi (Imperial College London) , Charlotte Millership (Imperial College London) , Fumiya Hoshiga (Imperial College London) , Rhodri M.l. Morgan (Imperial College London) , Paul Freemont (London Biofoundry, Imperial College Translation and Innovation Hub; Imperial College London; UK Dementia Research Institute Centre for Care Research and Technology, Imperial College London) , Angelika Gründling (Imperial College London)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Biological Chemistry , VOL 198

State: Published (Approved)
Published: October 2021

Abstract: Cyclic-di-adenosine monophosphate (c-di-AMP) is an important nucleotide signaling molecule that plays a key role in osmotic regulation in bacteria. c-di-AMP is produced from two molecules of ATP by proteins containing a diadenylate cyclase (DAC) domain. In Bacillus subtilis, the main c-di-AMP cyclase, CdaA, is a membrane-linked cyclase with an N-terminal transmembrane domain followed by the cytoplasmic DAC domain. As both high and low levels of c-di-AMP have a negative impact on bacterial growth, the cellular levels of this signaling nucleotide are tightly regulated. Here we investigated how the activity of the B. subtilis CdaA is regulated by the phosphoglucomutase GlmM, which has been shown to interact with the c-di-AMP cyclase. Using the soluble B. subtilis CdaACD catalytic domain and purified full-length GlmM or the GlmMF369 variant lacking the C-terminal flexible domain 4, we show that the cyclase and phosphoglucomutase form a stable complex in vitro and that GlmM is a potent cyclase inhibitor. We determined the crystal structure of the individual B. subtilis CdaACD and GlmM homodimers, and of the CdaACD:GlmMF369 complex. In the complex structure, a CdaACD dimer is bound to a GlmMF369 dimer in such a manner that GlmM blocks the oligomerization of CdaACD and formation of active head-to-head cyclase oligomers, thus suggesting a mechanism by which GlmM acts as a cyclase inhibitor. As the amino acids at the CdaACD:GlmM interphase are conserved, we propose that the observed mechanism of inhibition of CdaA by GlmM may also be conserved among Firmicutes.

Journal Keywords: Bacillus; cyclic dinucleotide; signalling; crystallography; protein structure

Diamond Keywords: Bacteria; Enzymes

Subject Areas: Biology and Bio-materials, Chemistry


Instruments: B21-High Throughput SAXS , I03-Macromolecular Crystallography

Added On: 25/10/2021 10:47

Discipline Tags:

Biochemistry Chemistry Structural biology Life Sciences & Biotech

Technical Tags:

Diffraction Scattering Macromolecular Crystallography (MX) Small Angle X-ray Scattering (SAXS)