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Marcus AH, Matsika S, Heussman D, Sorour MI, Maurer J, Albrecht CS, Enkhbaatar L, Herbert P, Kistler KA, von Hippel PH. Spectroscopic approaches for studies of site-specific DNA base and backbone 'breathing' using exciton-coupled dimer-labeled DNA. ARXIV 2024:arXiv:2403.16251v2. [PMID: 38584614 PMCID: PMC10996769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
DNA regulation and repair processes require direct interactions between proteins and DNA at specific sites. Local fluctuations of the sugar-phosphate backbones and bases of DNA (a form of DNA 'breathing') play a central role in such processes. Here we review the development and application of novel spectroscopic methods and analyses - both at the ensemble and single-molecule levels - to study structural and dynamic properties of exciton-coupled cyanine and fluorescent nucleobase analogue dimer-labeled DNA constructs at key positions involved in protein-DNA complex assembly and function. The exciton-coupled dimer probes act as 'sensors' of the local conformations adopted by the sugar-phosphate backbones and bases immediately surrounding the dimer probes. These methods can be used to study the mechanisms of protein binding and function at these sites.
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Affiliation(s)
- Andrew H. Marcus
- Center for Optical, Molecular and Quantum Science, Department of Chemistry and Biochemistry, University of Oregon, Eugene, Oregon 97403
- Institute of Molecular Biology, Department of Chemistry and Biochemistry, and University of Oregon, Eugene, Oregon 97403
| | - Spiridoula Matsika
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122
| | - Dylan Heussman
- Center for Optical, Molecular and Quantum Science, Department of Chemistry and Biochemistry, University of Oregon, Eugene, Oregon 97403
- Institute of Molecular Biology, Department of Chemistry and Biochemistry, and University of Oregon, Eugene, Oregon 97403
| | - Mohammed I. Sorour
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122
| | - Jack Maurer
- Center for Optical, Molecular and Quantum Science, Department of Chemistry and Biochemistry, University of Oregon, Eugene, Oregon 97403
- Institute of Molecular Biology, Department of Chemistry and Biochemistry, and University of Oregon, Eugene, Oregon 97403
| | - Claire S. Albrecht
- Center for Optical, Molecular and Quantum Science, Department of Physics, University of Oregon, Eugene, Oregon 97403
- Institute of Molecular Biology, Department of Physics, and University of Oregon, Eugene, Oregon 97403
| | - Lulu Enkhbaatar
- Center for Optical, Molecular and Quantum Science, Department of Chemistry and Biochemistry, University of Oregon, Eugene, Oregon 97403
- Institute of Molecular Biology, Department of Chemistry and Biochemistry, and University of Oregon, Eugene, Oregon 97403
| | - Patrick Herbert
- Center for Optical, Molecular and Quantum Science, Department of Chemistry and Biochemistry, University of Oregon, Eugene, Oregon 97403
- Institute of Molecular Biology, Department of Chemistry and Biochemistry, and University of Oregon, Eugene, Oregon 97403
| | - Kurt A. Kistler
- Department of Chemistry, Brandywine Campus, The Pennsylvania State University, Media, Pennsylvania 19063
| | - Peter H. von Hippel
- Institute of Molecular Biology, Department of Chemistry and Biochemistry, and University of Oregon, Eugene, Oregon 97403
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Yao S, Harder A, Darki F, Chang YW, Li A, Nikouei K, Volpe G, Lundström JN, Zeng J, Wray N, Lu Y, Sullivan PF, Leffler JH. Connecting genomic results for psychiatric disorders to human brain cell types and regions reveals convergence with functional connectivity. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.01.18.24301478. [PMID: 38410450 PMCID: PMC10896415 DOI: 10.1101/2024.01.18.24301478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
Understanding the temporal and spatial brain locations etiological for psychiatric disorders is essential for targeted neurobiological research. Integration of genomic insights from genome-wide association studies with single-cell transcriptomics is a powerful approach although past efforts have necessarily relied on mouse atlases. Leveraging a comprehensive atlas of the adult human brain, we prioritized cell types via the enrichment of SNP-heritabilities for brain diseases, disorders, and traits, progressing from individual cell types to brain regions. Our findings highlight specific neuronal clusters significantly enriched for the SNP-heritabilities for schizophrenia, bipolar disorder, and major depressive disorder along with intelligence, education, and neuroticism. Extrapolation of cell-type results to brain regions reveals important patterns for schizophrenia with distinct subregions in the hippocampus and amygdala exhibiting the highest significance. Cerebral cortical regions display similar enrichments despite the known prefrontal dysfunction in those with schizophrenia highlighting the importance of subcortical connectivity. Using functional MRI connectivity from cases with schizophrenia and neurotypical controls, we identified brain networks that distinguished cases from controls that also confirmed involvement of the central and lateral amygdala, hippocampal body, and prefrontal cortex. Our findings underscore the value of single-cell transcriptomics in decoding the polygenicity of psychiatric disorders and offer a promising convergence of genomic, transcriptomic, and brain imaging modalities toward common biological targets.
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Affiliation(s)
- Shuyang Yao
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - Arvid Harder
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - Fahimeh Darki
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Yu-Wei Chang
- Department of Physics, University of Gothenburg, Gothenburg, Sweden
| | - Ang Li
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
| | - Kasra Nikouei
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Giovanni Volpe
- Department of Physics, University of Gothenburg, Gothenburg, Sweden
| | - Johan N Lundström
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
- Monell Chemical Senses Center, Philadelphia, PA, USA
| | - Jian Zeng
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
| | - Naomi Wray
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
- Department of Psychiatry, University of Oxford, Oxford, UK
| | - Yi Lu
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - Patrick F Sullivan
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
- Departments of Genetics and Psychiatry, University of North Carolina, Chapel Hill, NC, USA
| | - Jens Hjerling Leffler
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
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Albrecht CS, Scatena LF, von Hippel PH, Marcus AH. Two-photon excitation two-dimensional fluorescence spectroscopy (2PE-2DFS) of the fluorescent nucleobase 6-MI. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2024; 12863:1286305. [PMID: 39149416 PMCID: PMC11326479 DOI: 10.1117/12.3001802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/17/2024]
Abstract
Base stacking is fundamentally important to the stability of double-stranded DNA. However, few experiments can directly probe the local conformations and conformational fluctuations of the DNA bases. Here we report a new spectroscopic approach to study the local conformations of DNA bases using the UV-absorbing fluorescent guanine analogue, 6-methyl isoxanthopterin (6-MI), which can be used as a site-specific probe to label DNA. In these experiments, we apply a two-photon excitation (2PE) approach to two-dimensional fluorescence spectroscopy (2DFS), which is a fluorescence-detected nonlinear Fourier transform spectroscopy. In 2DFS, a repeating sequence of four collinear laser pulses (with center wavelength ~ 675 nm and relative phases swept at radio frequencies) is used to excite the lowest energy electronic-vibrational (vibronic) transitions of 6-MI (with center wavelength ~ 340 nm). The ensuing low flux fluorescence is phase-synchronously detected at the level of individual photons and as a function of inter-pulse delay. The 2PE transition pathways that give rise to electronically excited state populations include optical coherences between electronic ground and excited states and non-resonant (one-photon-excited) virtual states. Our results indicate that 2PE-2DFS experiments can provide information about the electronic-vibrational spectrum of the 6-MI monomer, in addition to the conformation-dependent exciton coupling between adjacent 6-MI monomers within a (6-MI)2 dimer. In principle, this approach can be used to determine the local base-stacking conformations of (6-MI)2 dimer-substituted DNA constructs.
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Affiliation(s)
- Claire S Albrecht
- Center for Optical, Molecular and Quantum Science, University of Oregon, Eugene, Oregon 97403
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403
- Department of Physics, University of Oregon, Eugene, Oregon 97403
| | - Lawrence F Scatena
- Center for Optical, Molecular and Quantum Science, University of Oregon, Eugene, Oregon 97403
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, Oregon 97403
| | - Peter H von Hippel
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, Oregon 97403
| | - Andrew H Marcus
- Center for Optical, Molecular and Quantum Science, University of Oregon, Eugene, Oregon 97403
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, Oregon 97403
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Cashen BA, Morse M, Rouzina I, Karpel R, Williams M. Dynamic structure of T4 gene 32 protein filaments facilitates rapid noncooperative protein dissociation. Nucleic Acids Res 2023; 51:8587-8605. [PMID: 37449435 PMCID: PMC10484735 DOI: 10.1093/nar/gkad595] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 06/26/2023] [Accepted: 07/04/2023] [Indexed: 07/18/2023] Open
Abstract
Bacteriophage T4 gene 32 protein (gp32) is a model single-stranded DNA (ssDNA) binding protein, essential for DNA replication. gp32 forms cooperative filaments on ssDNA through interprotein interactions between its core and N-terminus. However, detailed understanding of gp32 filament structure and organization remains incomplete, particularly for longer, biologically-relevant DNA lengths. Moreover, it is unclear how these tightly-bound filaments dissociate from ssDNA during complementary strand synthesis. We use optical tweezers and atomic force microscopy to probe the structure and binding dynamics of gp32 on long (∼8 knt) ssDNA substrates. We find that cooperative binding of gp32 rigidifies ssDNA while also reducing its contour length, consistent with the ssDNA helically winding around the gp32 filament. While measured rates of gp32 binding and dissociation indicate nM binding affinity, at ∼1000-fold higher protein concentrations gp32 continues to bind into and restructure the gp32-ssDNA filament, leading to an increase in its helical pitch and elongation of the substrate. Furthermore, the oversaturated gp32-ssDNA filament becomes progressively unwound and unstable as observed by the appearance of a rapid, noncooperative protein dissociation phase not seen at lower complex saturation, suggesting a possible mechanism for prompt removal of gp32 from the overcrowded ssDNA in front of the polymerase during replication.
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Affiliation(s)
- Ben A Cashen
- Department of Physics, Northeastern University, Boston, MA 02115, USA
| | - Michael Morse
- Department of Physics, Northeastern University, Boston, MA 02115, USA
| | - Ioulia Rouzina
- Department of Chemistry and Biochemistry, Center for Retroviral Research and Center for RNA Biology, Ohio State University, Columbus, OH 43210, USA
| | - Richard L Karpel
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, MD 21250, USA
| | - Mark C Williams
- Department of Physics, Northeastern University, Boston, MA 02115, USA
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Marcus AH, Heussman D, Maurer J, Albrecht CS, Herbert P, von Hippel PH. Studies of Local DNA Backbone Conformation and Conformational Disorder Using Site-Specific Exciton-Coupled Dimer Probe Spectroscopy. Annu Rev Phys Chem 2023; 74:245-265. [PMID: 36696590 PMCID: PMC10590263 DOI: 10.1146/annurev-physchem-090419-041204] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The processes of genome expression, regulation, and repair require direct interactions between proteins and DNA at specific sites located at and near single-stranded-double-stranded DNA (ssDNA-dsDNA) junctions. Here, we review the application of recently developed spectroscopic methods and analyses that combine linear absorbance and circular dichroism spectroscopy with nonlinear 2D fluorescence spectroscopy to study the local conformations and conformational disorder of the sugar-phosphate backbones of ssDNA-dsDNA fork constructs that have been internally labeled with exciton-coupled cyanine (iCy3)2 dimer probes. With the application of these methods, the (iCy3)2 dimer can serve as a reliable probe of the mean local conformations and conformational distributions of the sugar-phosphate backbones of dsDNA at various critical positions. The results of our studies suggest a possible structural framework for understanding the roles of DNA breathing in driving the processes of protein-DNA complex assembly and function.
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Affiliation(s)
- Andrew H Marcus
- Center for Optical, Molecular and Quantum Science, University of Oregon, Eugene, Oregon, USA;
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, Oregon, USA
- Department of Physics, University of Oregon, Eugene, Oregon, USA
| | - Dylan Heussman
- Center for Optical, Molecular and Quantum Science, University of Oregon, Eugene, Oregon, USA;
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, Oregon, USA
| | - Jack Maurer
- Center for Optical, Molecular and Quantum Science, University of Oregon, Eugene, Oregon, USA;
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, Oregon, USA
| | - Claire S Albrecht
- Center for Optical, Molecular and Quantum Science, University of Oregon, Eugene, Oregon, USA;
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
- Department of Physics, University of Oregon, Eugene, Oregon, USA
| | - Patrick Herbert
- Center for Optical, Molecular and Quantum Science, University of Oregon, Eugene, Oregon, USA;
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, Oregon, USA
| | - Peter H von Hippel
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon, USA
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, Oregon, USA
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Jose D, Michael MM, Bentsen C, Rosenblum B, Zelaya A. A Spectroscopic Approach to Unravel the Local Conformations of a G-Quadruplex Using CD-Active Fluorescent Base Analogues. Biochemistry 2022; 61:2720-2732. [DOI: 10.1021/acs.biochem.2c00461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Davis Jose
- Department of Chemistry and Physics, Monmouth University, West Long Branch, New Jersey07764, United States
| | - Miya Mary Michael
- Department of Chemistry and Physics, Monmouth University, West Long Branch, New Jersey07764, United States
| | - Christopher Bentsen
- Department of Chemistry and Physics, Monmouth University, West Long Branch, New Jersey07764, United States
| | - Brandon Rosenblum
- Department of Chemistry and Physics, Monmouth University, West Long Branch, New Jersey07764, United States
| | - Adriana Zelaya
- Department of Chemistry and Physics, Monmouth University, West Long Branch, New Jersey07764, United States
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Linder J, Koplik SE, Kundaje A, Seelig G. Deciphering the impact of genetic variation on human polyadenylation using APARENT2. Genome Biol 2022; 23:232. [PMID: 36335397 PMCID: PMC9636789 DOI: 10.1186/s13059-022-02799-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 10/19/2022] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND 3'-end processing by cleavage and polyadenylation is an important and finely tuned regulatory process during mRNA maturation. Numerous genetic variants are known to cause or contribute to human disorders by disrupting the cis-regulatory code of polyadenylation signals. Yet, due to the complexity of this code, variant interpretation remains challenging. RESULTS We introduce a residual neural network model, APARENT2, that can infer 3'-cleavage and polyadenylation from DNA sequence more accurately than any previous model. This model generalizes to the case of alternative polyadenylation (APA) for a variable number of polyadenylation signals. We demonstrate APARENT2's performance on several variant datasets, including functional reporter data and human 3' aQTLs from GTEx. We apply neural network interpretation methods to gain insights into disrupted or protective higher-order features of polyadenylation. We fine-tune APARENT2 on human tissue-resolved transcriptomic data to elucidate tissue-specific variant effects. By combining APARENT2 with models of mRNA stability, we extend aQTL effect size predictions to the entire 3' untranslated region. Finally, we perform in silico saturation mutagenesis of all human polyadenylation signals and compare the predicted effects of [Formula: see text] million variants against gnomAD. While loss-of-function variants were generally selected against, we also find specific clinical conditions linked to gain-of-function mutations. For example, we detect an association between gain-of-function mutations in the 3'-end and autism spectrum disorder. To experimentally validate APARENT2's predictions, we assayed clinically relevant variants in multiple cell lines, including microglia-derived cells. CONCLUSIONS A sequence-to-function model based on deep residual learning enables accurate functional interpretation of genetic variants in polyadenylation signals and, when coupled with large human variation databases, elucidates the link between functional 3'-end mutations and human health.
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Affiliation(s)
| | | | - Anshul Kundaje
- Department of Genetics, Stanford University, Stanford, USA
- Department of Computer Science, Stanford University, Stanford, USA
| | - Georg Seelig
- Paul G. Allen School of Computer Science and Engineering, University of Washington, Seattle, USA
- Department of Electrical and Computer Engineering, University of Washington, Seattle, USA
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Li X, Yang H, He J, Yang B, Zhao Y, Wu P. Full liberation of 2-Aminopurine with nucleases digestion for highly sensitive biosensing. Biosens Bioelectron 2022; 196:113721. [PMID: 34673482 DOI: 10.1016/j.bios.2021.113721] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/09/2021] [Accepted: 10/15/2021] [Indexed: 02/05/2023]
Abstract
2-Aminopurine (2-AP), a fluorescent isomer of adenine, is a popular fluorescent tag for DNA-based biosensors. The fluorescence of 2-AP is highly dependent on its microenvironment, i.e., almost non-fluorescent and merely fluorescent in dsDNA and ssDNA, respectively, but can be greatly brightened as mononucleotide. In most 2-AP-based biosensors, DNA transformation from dsDNA to ssDNA was employed, while selective digestion of 2-AP-labeled DNA with nucleases represents an appealing approach for improving the biosensor sensitivity. However, some detailed fundamental information, such as the reason for nuclease digestion, the influence of the labeling site, neighboring bases, or the label number of 2-AP for final signal output, are still largely unknown, which greatly limits the utility of 2-AP-based biosensors. In this work, using both steady- and excited-state fluorescence (lifetime), we demonstrated that nuclease digestion resulted in almost full liberation of 2-AP mononucleotides, and was free from labeling site and neighboring bases. Furthermore, we also found that nuclease digestion could lead to multiplexed sensitivity from increasing number of 2-AP labelling, but was not achievable for the conventional biosensors without full liberation of 2-AP. Considering the popularity of 2-AP in biosensing and other related applications, the above obtained information in sensitivity boosting is fundamentally important for future design of 2-AP-based biosensors.
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Affiliation(s)
- Xianming Li
- Department of Rheumatology and Immunology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Hang Yang
- Department of Rheumatology and Immunology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Jialun He
- Analytical & Testing Center, Sichuan University, Chengdu, 610064, China
| | - Bin Yang
- Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, 610041, China.
| | - Yi Zhao
- Department of Rheumatology and Immunology, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Peng Wu
- Analytical & Testing Center, Sichuan University, Chengdu, 610064, China.
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Blevins MS, Walker JN, Schaub JM, Finkelstein IJ, Brodbelt JS. Characterization of the T4 gp32-ssDNA complex by native, cross-linking, and ultraviolet photodissociation mass spectrometry. Chem Sci 2021; 12:13764-13776. [PMID: 34760161 PMCID: PMC8549804 DOI: 10.1039/d1sc02861h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 09/23/2021] [Indexed: 12/28/2022] Open
Abstract
Protein-DNA interactions play crucial roles in DNA replication across all living organisms. Here, we apply a suite of mass spectrometry (MS) tools to characterize a protein-ssDNA complex, T4 gp32·ssDNA, with results that both support previous studies and simultaneously uncover novel insight into this non-covalent biological complex. Native mass spectrometry of the protein reveals the co-occurrence of Zn-bound monomers and homodimers, while addition of differing lengths of ssDNA generates a variety of protein:ssDNA complex stoichiometries (1 : 1, 2 : 1, 3 : 1), indicating sequential association of gp32 monomers with ssDNA. Ultraviolet photodissociation (UVPD) mass spectrometry allows characterization of the binding site of the ssDNA within the protein monomer via analysis of holo ions, i.e. ssDNA-containing protein fragments, enabling interrogation of disordered regions of the protein which are inaccessible via traditional crystallographic techniques. Finally, two complementary cross-linking (XL) approaches, bottom-up analysis of the crosslinked complexes as well as MS1 analysis of the intact complexes, are used to showcase the absence of ssDNA binding with the intact cross-linked homodimer and to generate two homodimer gp32 model structures which highlight that the homodimer interface overlaps with the monomer ssDNA-binding site. These models suggest that the homodimer may function in a regulatory capacity by controlling the extent of ssDNA binding of the protein monomer. In sum, this work underscores the utility of a multi-faceted mass spectrometry approach for detailed investigation of non-covalent protein-DNA complexes.
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Affiliation(s)
- Molly S Blevins
- Department of Chemistry, University of Texas at Austin Austin TX 78712 USA
| | - Jada N Walker
- Department of Chemistry, University of Texas at Austin Austin TX 78712 USA
| | - Jeffrey M Schaub
- Department of Molecular Biosciences, University of Texas at Austin Austin TX 78712 USA
| | - Ilya J Finkelstein
- Department of Molecular Biosciences, University of Texas at Austin Austin TX 78712 USA
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