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Vernon TN, Terrell JR, Albrecht AV, Germann MW, Wilson WD, Poon GMK. Dissection of integrated readout reveals the structural thermodynamics of DNA selection by transcription factors. Structure 2024; 32:83-96.e4. [PMID: 38042148 DOI: 10.1016/j.str.2023.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 10/12/2023] [Accepted: 11/07/2023] [Indexed: 12/04/2023]
Abstract
Nucleobases such as inosine have been extensively utilized to map direct contacts by proteins in the DNA groove. Their deployment as targeted probes of dynamics and hydration, which are dominant thermodynamic drivers of affinity and specificity, has been limited by a paucity of suitable experimental models. We report a joint crystallographic, thermodynamic, and computational study of the bidentate complex of the arginine side chain with a Watson-Crick guanine (Arg×GC), a highly specific configuration adopted by major transcription factors throughout the eukaryotic branches in the Tree of Life. Using the ETS-family factor PU.1 as a high-resolution structural framework, inosine substitution for guanine resulted in a sharp dissection of conformational dynamics and hydration and elucidated their role in the DNA specificity of PU.1. Our work suggests an under-exploited utility of modified nucleobases in untangling the structural thermodynamics of interactions, such as the Arg×GC motif, where direct and indirect readout are tightly integrated.
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Affiliation(s)
- Tyler N Vernon
- Department of Chemistry, Georgia State University, Atlanta, GA 30302, USA
| | - J Ross Terrell
- Department of Chemistry, Georgia State University, Atlanta, GA 30302, USA
| | - Amanda V Albrecht
- Department of Chemistry, Georgia State University, Atlanta, GA 30302, USA
| | - Markus W Germann
- Department of Chemistry, Georgia State University, Atlanta, GA 30302, USA; Department of Biology, Georgia State University, Atlanta, GA 30302, USA.
| | - W David Wilson
- Department of Chemistry, Georgia State University, Atlanta, GA 30302, USA; Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30302, USA.
| | - Gregory M K Poon
- Department of Chemistry, Georgia State University, Atlanta, GA 30302, USA; Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30302, USA.
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Terrell JR, Taylor SJ, Schneider AL, Lu Y, Vernon TN, Xhani S, Gumpper RH, Luo M, Wilson WD, Steidl U, Poon GMK. DNA selection by the master transcription factor PU.1. Cell Rep 2023; 42:112671. [PMID: 37352101 PMCID: PMC10479921 DOI: 10.1016/j.celrep.2023.112671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 04/07/2023] [Accepted: 06/02/2023] [Indexed: 06/25/2023] Open
Abstract
The master transcriptional regulator PU.1/Spi-1 engages DNA sites with affinities spanning multiple orders of magnitude. To elucidate this remarkable plasticity, we have characterized 22 high-resolution co-crystallographic PU.1/DNA complexes across the addressable affinity range in myeloid gene transactivation. Over a purine-rich core (such as 5'-GGAA-3') flanked by variable sequences, affinity is negotiated by direct readout on the 5' flank via a critical glutamine (Q226) sidechain and by indirect readout on the 3' flank by sequence-dependent helical flexibility. Direct readout by Q226 dynamically specifies PU.1's characteristic preference for purines and explains the pathogenic mutation Q226E in Waldenström macroglobulinemia. The structures also reveal how disruption of Q226 mediates strand-specific inhibition by DNA methylation and the recognition of non-canonical sites, including the authentic binding sequence at the CD11b promoter. A re-synthesis of phylogenetic and structural data on the ETS family, considering the centrality of Q226 in PU.1, unifies the model of DNA selection by ETS proteins.
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Affiliation(s)
- J Ross Terrell
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA
| | - Samuel J Taylor
- Departments of Cell Biology, Oncology, and Medicine, Ruth L. and David S. Gottesman Institute for Stem Cell Research and Regenerative Medicine, Blood Cancer Institute, and the Montefiore Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Amelia L Schneider
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA
| | - Yue Lu
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA
| | - Tyler N Vernon
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA
| | - Suela Xhani
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA
| | - Ryan H Gumpper
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA
| | - Ming Luo
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA; Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303, USA
| | - W David Wilson
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA; Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303, USA
| | - Ulrich Steidl
- Departments of Cell Biology, Oncology, and Medicine, Ruth L. and David S. Gottesman Institute for Stem Cell Research and Regenerative Medicine, Blood Cancer Institute, and the Montefiore Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | - Gregory M K Poon
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA; Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA 30303, USA.
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