A Water-Bridged Cysteine-Cysteine Redox Regulation Mechanism in Bacterial Protein Tyrosine Phosphatases

Abstract

SummaryThe emergence of multidrug-resistant Mycobacterium tuberculosis (Mtb) strains highlights the need to develop more efficacious and potent drugs. However, this goal is dependent on a comprehensive understanding of Mtb virulence protein effectors at the molecular level. Here, we used a post-expression cysteine (Cys)-to-dehydrolanine (Dha) chemical editing strategy to identify a water-mediated motif that modulates accessibility of the protein tyrosine phosphatase A (PtpA) catalytic pocket. Importantly, this water-mediated Cys-Cys non-covalent motif is also present in the phosphatase SptpA from Staphylococcus aureus, which suggests a potentially preserved structural feature among bacterial tyrosine phosphatases. The identification of this structural water provides insight into the known resistance of Mtb PtpA to the oxidative conditions that prevail within an infected host macrophage. This strategy could be applied to extend the understanding of the dynamics and function(s) of proteins in their native state and ultimately aid in the design of small-molecule modulators.

Dehydroamino acid chemical biology: an example of functional group interconversion on proteins

“… 34 DBHDA was used to regioselectively transform single cysteines to Dha residues in bacterial phosphatases. 35 The study illustrates the utility of Dha as a chemical and spectroscopic reporter for reactivity mapping in proteins containing multiple cysteines.…”

The Critical Role of Non-catalytic Cysteine Residues in Proteins

“…I then moved to Cambridge to work with him in the Department of Chemistry. In this issue of Chem, 5 we demonstrated the results of this pioneering approach. At first, we aimed to test the selectivity of chemical mutagenesis in proteins with multiple naturally occurring cysteines.…”

Unveiling Druggable Pockets by Site-Specific Protein Modification: Beyond Antibody-Drug Conjugates

“…Similar results were also obtained with the protein tyrosine phosphatase YopH from Yersinia enterecolitica in which Cys259 was preferentially modified over the catalytic Cys403. These examples highlighted the sitespecific modification of non-catalytic cysteines and presented very promising sites for the allosteric inhibition of bacterial phosphatases (Bertoldo et al, 2017(Bertoldo et al, , 2018. Since most drug discovery approaches rely on competitive inhibitors targeting the catalytic pocket, these sites might allow an alternative route to develop irreversible and highly selective inhibitors.…”