The Legionella pneumophila effector SidL is an adenylyltransferase that modifies the glycolytic intermediate 3-phosphoglycerate.

The large effector arsenal of the bacterial pathogen Legionella pneumophila has been a rich source of biochemistry, highlighting the immense diversity of strategies deployed in host-pathogen conflict. Here, we redefine the purported translation inhibitor SidL as an adenylyltransferase that targets a glycolytic metabolite, discovering that it modifies 3-phosphoglycerate with adenosine monophosphate (AMP) to produce the previously unknown molecule 2-AMP-3-phosphoglycerate. When expressed alone in mammalian cells, SidL adenylates 3-phosphoglycerate, disrupts glycolysis, and blocks the nutrient-responsive translation regulator mTORC1, which we propose indirectly causes translation inhibition. Moreover, we observe SidL-dependent production of 2-AMP-3-phosphoglycerate in macrophages during L. pneumophila infection, the timing of which is consistent with a role for SidL in the early stages of the infection cycle. Thus, our study uncovers a mechanism by which an intracellular pathogen uses the chemical modification of a glycolytic intermediate to target central carbon metabolism in the host.