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Gade M, Tan LL, Damry AM, Sandhu M, Brock JS, Delaney A, Villar-Briones A, Jackson CJ, Laurino P. Substrate Dynamics Contribute to Enzymatic Specificity in Human and Bacterial Methionine Adenosyltransferases. JACS Au 2021; 1:2349-2360. [PMID: 34977903 PMCID: PMC8715544 DOI: 10.1021/jacsau.1c00464] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Indexed: 05/14/2023]
Abstract
Protein conformational changes can facilitate the binding of noncognate substrates and underlying promiscuous activities. However, the contribution of substrate conformational dynamics to this process is comparatively poorly understood. Here, we analyze human (hMAT2A) and Escherichia coli (eMAT) methionine adenosyltransferases that have identical active sites but different substrate specificity. In the promiscuous hMAT2A, noncognate substrates bind in a stable conformation to allow catalysis. In contrast, noncognate substrates sample stable productive binding modes less frequently in eMAT owing to altered mobility in the enzyme active site. Different cellular concentrations of substrates likely drove the evolutionary divergence of substrate specificity in these orthologues. The observation of catalytic promiscuity in hMAT2A led to the detection of a new human metabolite, methyl thioguanosine, that is produced at elevated levels in a cancer cell line. This work establishes that identical active sites can result in different substrate specificity owing to the effects of substrate and enzyme dynamics.
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Affiliation(s)
- Madhuri Gade
- Protein
Engineering and Evolution Unit, Okinawa
Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna 904-0495, Okinawa, Japan
| | - Li Lynn Tan
- Research
School of Chemistry, Australian National
University, Canberra, 2601, Australia
| | - Adam M. Damry
- Research
School of Chemistry, Australian National
University, Canberra, 2601, Australia
| | - Mahakaran Sandhu
- Research
School of Chemistry, Australian National
University, Canberra, 2601, Australia
| | - Joseph S. Brock
- Research
School of Biology, Australian National University, Canberra 2601, Australia
| | - Andie Delaney
- Research
School of Chemistry, Australian National
University, Canberra, 2601, Australia
| | - Alejandro Villar-Briones
- Protein
Engineering and Evolution Unit, Okinawa
Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna 904-0495, Okinawa, Japan
| | - Colin J. Jackson
- Research
School of Chemistry, Australian National
University, Canberra, 2601, Australia
- Australian
Research Council Centre of Excellence for Innovations in Peptide and
Protein Science, Research School of Chemistry, Australian National University, Canberra 2601, ACT, Australia
- Australian
Research Council Centre of Excellence in Synthetic Biology, Research
School of Chemistry, Australian National
University, Canberra 2601, ACT, Australia
| | - Paola Laurino
- Protein
Engineering and Evolution Unit, Okinawa
Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna 904-0495, Okinawa, Japan
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