Abstract
Legionella pneumophila infects eukaryotic cells by forming a replicative organelle - the Legionella containing vacuole. During this process, the bacterial protein DrrA/SidM is secreted and manipulates the activity and post-translational modification (PTM) states of the vesicular trafficking regulator Rab1. As a result, Rab1 is modified with an adenosine monophosphate (AMP), and this process is referred to as AMPylation. Here, we use a chemical approach to stabilise low-affinity Rab:DrrA complexes in a site-specific manner to gain insight into the molecular basis of the interaction between the Rab protein and the AMPylation domain of DrrA. The crystal structure of the Rab:DrrA complex reveals a previously unknown non-conventional Rab-binding site (NC-RBS). Biochemical characterisation demonstrates allosteric stimulation of the AMPylation activity of DrrA via Rab binding to the NC-RBS. We speculate that allosteric control of DrrA could in principle prevent random and potentially cytotoxic AMPylation in the host, thereby perhaps ensuring efficient infection by Legionella.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adenosine Monophosphate / metabolism*
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Allosteric Regulation
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Bacterial Proteins / genetics
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Bacterial Proteins / isolation & purification
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Bacterial Proteins / metabolism*
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Bacterial Proteins / ultrastructure
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Binding Sites / genetics
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Crystallography, X-Ray
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Guanine Nucleotide Exchange Factors / genetics
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Guanine Nucleotide Exchange Factors / isolation & purification
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Guanine Nucleotide Exchange Factors / metabolism*
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Guanine Nucleotide Exchange Factors / ultrastructure
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Guanosine Triphosphate / metabolism
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Humans
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Legionella pneumophila / metabolism
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Legionella pneumophila / pathogenicity*
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Legionnaires' Disease / microbiology
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Legionnaires' Disease / pathology*
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Macrophages, Alveolar / metabolism
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Macrophages, Alveolar / microbiology
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Phagocytosis
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Protein Binding
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Protein Processing, Post-Translational
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Recombinant Proteins / genetics
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Recombinant Proteins / isolation & purification
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Recombinant Proteins / metabolism
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Recombinant Proteins / ultrastructure
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rab1 GTP-Binding Proteins / genetics
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rab1 GTP-Binding Proteins / isolation & purification
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rab1 GTP-Binding Proteins / metabolism*
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rab1 GTP-Binding Proteins / ultrastructure
Substances
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Bacterial Proteins
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Guanine Nucleotide Exchange Factors
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Recombinant Proteins
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SidM protein, Legionella pneumophila
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Adenosine Monophosphate
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Guanosine Triphosphate
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Rab1B protein, human
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rab1 GTP-Binding Proteins