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  1. Article: Self-Consistent Parameterization of DNA Residues for the Non-Polarizable AMBER Force Fields.

    Schneider, Amelia L / Albrecht, Amanda V / Huang, Kenneth / Germann, Markus W / Poon, Gregory M K

    Life (Basel, Switzerland)

    2022  Volume 12, Issue 5

    Abstract: Fixed-charge (non-polarizable) forcefields are accurate and computationally efficient tools for modeling the molecular dynamics of nucleic acid polymers, particularly DNA, well into the µs timescale. The continued utility of these forcefields depends in ... ...

    Abstract Fixed-charge (non-polarizable) forcefields are accurate and computationally efficient tools for modeling the molecular dynamics of nucleic acid polymers, particularly DNA, well into the µs timescale. The continued utility of these forcefields depends in part on expanding the residue set in step with advancing nucleic acid chemistry and biology. A key step in parameterizing new residues is charge derivation which is self-consistent with the existing residues. As atomic charges are derived by fitting against molecular electrostatic potentials, appropriate structural models are critical. Benchmarking against the existing charge set used in current AMBER nucleic acid forcefields, we report that quantum mechanical models of deoxynucleosides, even at a high level of theory, are not optimal structures for charge derivation. Instead, structures from molecular mechanics minimization yield charges with up to 6-fold lower RMS deviation from the published values, due to the choice of such an approach in the derivation of the original charge set. We present a contemporary protocol for rendering self-consistent charges as well as optimized charges for a panel of nine non-canonical residues that will permit comparison with literature as well as studying the dynamics of novel DNA polymers.
    Language English
    Publishing date 2022-04-30
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2662250-6
    ISSN 2075-1729
    ISSN 2075-1729
    DOI 10.3390/life12050666
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: DNA-facilitated target search by nucleoproteins: Extension of a biosensor-surface plasmon resonance method

    Vo, Tam D. / Schneider, Amelia L. / Poon, Gregory M.K. / Wilson, W. David

    Analytical biochemistry. 2021 Sept. 15, v. 629

    2021  

    Abstract: To extend the value of biosensor-SPR in the characterization of DNA recognition by nucleoproteins, we report a comparative analysis of DNA-facilitated target search by two ETS-family transcription factors: Elk1 and ETV6. ETS domains represent an ... ...

    Abstract To extend the value of biosensor-SPR in the characterization of DNA recognition by nucleoproteins, we report a comparative analysis of DNA-facilitated target search by two ETS-family transcription factors: Elk1 and ETV6. ETS domains represent an attractive system for developing biosensor-based techniques due to a broad range of physicochemical properties encoded within a highly conserved DNA-binding motif. Building on a biosensor approach in which the protein is quantitatively sequestered and presented to immobilized cognate DNA as nonspecific complexes, we assessed the impact of intrinsic cognate and nonspecific affinities on long-range (intersegmental) target search. The equilibrium constants of DNA-facilitated binding were sensitive to the intrinsic binding properties of the proteins such that their relative specificity for cognate DNA were reinforced when binding occurred by transfer vs. without nonspecific DNA. Direct measurement of association and dissociation kinetics revealed ionic features of the activated complex that evidenced DNA-facilitated dissociation, even though Elk1 and ETV6 harbor only a single DNA-binding surface. At salt concentrations that masked the effects of nonspecific pre-binding at equilibrium, the dissociation kinetics of cognate binding were nevertheless distinct from conditions under which nonspecific DNA was absent. These results further strengthen the significance of long-range DNA-facilitated translocation in the physiologic environment.
    Keywords DNA ; biosensors ; dissociation ; nucleoproteins
    Language English
    Dates of publication 2021-0915
    Publishing place Elsevier Inc.
    Document type Article
    ZDB-ID 1110-1
    ISSN 1096-0309 ; 0003-2697
    ISSN (online) 1096-0309
    ISSN 0003-2697
    DOI 10.1016/j.ab.2021.114298
    Database NAL-Catalogue (AGRICOLA)

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  3. Article ; Online: Salt bridge dynamics in protein/DNA recognition: a comparative analysis of Elk1 and ETV6.

    Vo, Tam D / Schneider, Amelia L / Wilson, W David / Poon, Gregory M K

    Physical chemistry chemical physics : PCCP

    2021  Volume 23, Issue 24, Page(s) 13490–13502

    Abstract: Electrostatic protein/DNA interactions arise from the neutralization of the DNA phosphodiester backbone as well as coupled exchanges by charged protein residues as salt bridges or with mobile ions. Much focus has been and continues to be paid to ... ...

    Abstract Electrostatic protein/DNA interactions arise from the neutralization of the DNA phosphodiester backbone as well as coupled exchanges by charged protein residues as salt bridges or with mobile ions. Much focus has been and continues to be paid to interfacial ion pairs with DNA. The role of extra-interfacial ionic interactions, particularly as dynamic drivers of DNA sequence selectivity, remain poorly known. The ETS family of transcription factors represents an attractive model for addressing this knowledge gap given their diverse ionic composition in primary structures that fold to a tightly conserved DNA-binding motif. To probe the importance of extra-interfacial salt bridges in DNA recognition, we compared the salt-dependent binding by Elk1 with ETV6, two ETS homologs differing markedly in ionic composition. While both proteins exhibit salt-dependent binding with cognate DNA that corresponds to interfacial phosphate contacts, their nonspecific binding diverges from cognate binding as well as each other. Molecular dynamics simulations in explicit solvent, which generated ionic interactions in agreement with the experimental binding data, revealed distinct salt-bridge dynamics in the nonspecific complexes formed by the two proteins. Impaired DNA contact by ETV6 resulted in fewer backbone contacts in the nonspecific complex, while Elk1 exhibited a redistribution of extra-interfacial salt bridges via residues that are non-conserved between the two ETS relatives. Thus, primary structure variation in ionic residues can encode highly differentiated specificity mechanisms in a highly conserved DNA-binding motif.
    MeSH term(s) DNA/chemistry ; Density Functional Theory ; Humans ; Molecular Dynamics Simulation ; Proto-Oncogene Proteins c-ets/chemistry ; Repressor Proteins/chemistry ; ets-Domain Protein Elk-1/chemistry ; ETS Translocation Variant 6 Protein
    Chemical Substances ELK1 protein, human ; Proto-Oncogene Proteins c-ets ; Repressor Proteins ; ets-Domain Protein Elk-1 ; DNA (9007-49-2)
    Language English
    Publishing date 2021-06-13
    Publishing country England
    Document type Comparative Study ; Journal Article
    ZDB-ID 1476244-4
    ISSN 1463-9084 ; 1463-9076
    ISSN (online) 1463-9084
    ISSN 1463-9076
    DOI 10.1039/d1cp01568k
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: DNA-facilitated target search by nucleoproteins: Extension of a biosensor-surface plasmon resonance method.

    Vo, Tam D / Schneider, Amelia L / Poon, Gregory M K / Wilson, W David

    Analytical biochemistry

    2021  Volume 629, Page(s) 114298

    Abstract: To extend the value of biosensor-SPR in the characterization of DNA recognition by nucleoproteins, we report a comparative analysis of DNA-facilitated target search by two ETS-family transcription factors: Elk1 and ETV6. ETS domains represent an ... ...

    Abstract To extend the value of biosensor-SPR in the characterization of DNA recognition by nucleoproteins, we report a comparative analysis of DNA-facilitated target search by two ETS-family transcription factors: Elk1 and ETV6. ETS domains represent an attractive system for developing biosensor-based techniques due to a broad range of physicochemical properties encoded within a highly conserved DNA-binding motif. Building on a biosensor approach in which the protein is quantitatively sequestered and presented to immobilized cognate DNA as nonspecific complexes, we assessed the impact of intrinsic cognate and nonspecific affinities on long-range (intersegmental) target search. The equilibrium constants of DNA-facilitated binding were sensitive to the intrinsic binding properties of the proteins such that their relative specificity for cognate DNA were reinforced when binding occurred by transfer vs. without nonspecific DNA. Direct measurement of association and dissociation kinetics revealed ionic features of the activated complex that evidenced DNA-facilitated dissociation, even though Elk1 and ETV6 harbor only a single DNA-binding surface. At salt concentrations that masked the effects of nonspecific pre-binding at equilibrium, the dissociation kinetics of cognate binding were nevertheless distinct from conditions under which nonspecific DNA was absent. These results further strengthen the significance of long-range DNA-facilitated translocation in the physiologic environment.
    MeSH term(s) Binding Sites ; Biosensing Techniques ; DNA/analysis ; Escherichia coli/genetics ; Nucleoproteins/chemistry ; Nucleoproteins/genetics ; Protein Binding ; Proto-Oncogene Proteins c-ets/chemistry ; Repressor Proteins/chemistry ; Surface Plasmon Resonance ; ets-Domain Protein Elk-1/chemistry ; ETS Translocation Variant 6 Protein
    Chemical Substances Nucleoproteins ; Proto-Oncogene Proteins c-ets ; Repressor Proteins ; ets-Domain Protein Elk-1 ; DNA (9007-49-2)
    Language English
    Publishing date 2021-07-10
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 1110-1
    ISSN 1096-0309 ; 0003-2697
    ISSN (online) 1096-0309
    ISSN 0003-2697
    DOI 10.1016/j.ab.2021.114298
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: DNA selection by the master transcription factor PU.1.

    Terrell, J Ross / Taylor, Samuel J / Schneider, Amelia L / Lu, Yue / Vernon, Tyler N / Xhani, Suela / Gumpper, Ryan H / Luo, Ming / Wilson, W David / Steidl, Ulrich / Poon, Gregory M K

    Cell reports

    2023  Volume 42, Issue 7, Page(s) 112671

    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 ... ...

    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.
    MeSH term(s) Phylogeny ; Binding Sites ; Trans-Activators/metabolism ; DNA/metabolism
    Chemical Substances proto-oncogene protein Spi-1 ; Trans-Activators ; DNA (9007-49-2)
    Language English
    Publishing date 2023-06-22
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, U.S. Gov't, Non-P.H.S. ; Research Support, Non-U.S. Gov't
    ZDB-ID 2649101-1
    ISSN 2211-1247 ; 2211-1247
    ISSN (online) 2211-1247
    ISSN 2211-1247
    DOI 10.1016/j.celrep.2023.112671
    Database MEDical Literature Analysis and Retrieval System OnLINE

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