Identification of Widespread Adenosine Nucleotide Binding in Mycobacterium tuberculosis

SummaryComputational prediction of protein function is frequently error-prone and incomplete. In Mycobacterium tuberculosis (Mtb), ∼25% of all genes have no predicted function and are annotated as hypothetical proteins, severely limiting our understanding of Mtb pathogenicity. Here, we utilize a high-throughput quantitative activity-based protein profiling (ABPP) platform to probe, annotate, and validate ATP-binding proteins in Mtb. We experimentally validate prior in silico predictions of >240 proteins and identify 72 hypothetical proteins as ATP binders. ATP interacts with proteins with diverse and unrelated sequences, providing an expanded view of adenosine nucleotide binding in Mtb. Several hypothetical ATP binders are essential or taxonomically limited, suggesting specialized functions in mycobacterial physiology and pathogenicity.

► Over 250 Mtb ATP-binding proteins validated experimentally
► Seventy-two hypothetical Mtb proteins are previously unrecognized adenosine binders
► The essential ESX-1 proteins Rv3614c-3616c have ATP binding activity