Дисертації з теми "Single Stranded DNA Binding Protein (SSBb)"
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Bain, Amanda Louise. "Investigation of the Physiological Role of Ssb1 using an in-vivo Targeted Mouse Model." Thesis, Griffith University, 2013. http://hdl.handle.net/10072/366937.
Повний текст джерелаThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Biomolecular and Physical Sciences
Science, Environment, Engineering and Technology
Full Text
Jordan, Christian. "Helicase-SSB Interactions In Recombination-Dependent DNA Repair and Replication." ScholarWorks @ UVM, 2014. http://scholarworks.uvm.edu/graddis/270.
Повний текст джерелаIn, Junghoon Erie Dorothy A. "Structure-function studies of late stages of E. Coli MMR interaction of DNA helicase II with single-stranded DNA binding protein SSB and MutL /." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2008. http://dc.lib.unc.edu/u?/etd,2053.
Повний текст джерелаTitle from electronic title page (viewed Feb. 17, 2009). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Curriculum in Applied and Material Sciences." Discipline: Applied and Materials Sciences; Department/School: Applied and Materials Sciences.
Nag, Purba. "Delineating the overlapping roles of the single-stranded DNA binding proteins Ssb1 and Ssb2 in the maintenance of genomic stability and intestinal homeostasis." Thesis, Griffith University, 2019. http://hdl.handle.net/10072/384796.
Повний текст джерелаThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environment and Sc
Science, Environment, Engineering and Technology
Full Text
Johnson, Vinu. "Structural and Biophysical Studies of Single-Stranded DNA Binding Proteins and dnaB Helicases, Proteins Involved in DNA Replication and Repair." University of Toledo / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1198939056.
Повний текст джерелаHowland, Christopher James. "The single-stranded DNA-binding protein gene of plasmid Colib-P9." Thesis, University of Leicester, 1989. http://hdl.handle.net/2381/34428.
Повний текст джерелаStroud, A. L. "Genetic analysis of RPA single-stranded DNA binding protein in Haloferax volcanii." Thesis, University of Nottingham, 2012. http://eprints.nottingham.ac.uk/12623/.
Повний текст джерелаMorten, Michael J. "Developing novel single molecule analyses of the single-stranded DNA binding protein from Sulfolobus solfataricus." Thesis, University of St Andrews, 2015. http://hdl.handle.net/10023/7568.
Повний текст джерелаDodd, Isabel. "Characterisation of the single-stranded DNA binding protein encoded by Kaposi's sarcoma herpesvirus." Thesis, Cranfield University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.421241.
Повний текст джерелаAshton, Nicholas W. "Characterisation of human single-stranded DNA-binding protein 1 (hSSB1) regulation by post-translational modifications." Thesis, Queensland University of Technology, 2016. https://eprints.qut.edu.au/98660/1/Nicholas_Ashton_Thesis.pdf.
Повний текст джерелаBoutemy, Laurence S. "Analysis of the Interactions between the 5' to 3' Exonuclease and the Single-Stranded DNA-Binding Protein from Bacteriophage T4 and Related Phages." Connect to full text in OhioLINK ETD Center, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1223979052.
Повний текст джерелаTypescript. "Submitted as partial fulfillment of the requirements for the Doctor of Philosophy in Chemistry." Includes bibliographical references (leaves 305-309).
Jaffary, Syed Ali Naqi Raza. "The human single-stranded DNA binding protein 2 (HSSB2) and its novel role in the base excision repair pathway." Thesis, Queensland University of Technology, 2018. https://eprints.qut.edu.au/119175/1/Syed%20Ali%20Naqi%20Raza_Jaffary_Thesis.pdf.
Повний текст джерелаFisher, Mark. "Intra and extracellular responses to DNA damage." Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/214106/1/Mark_Fisher_Thesis.pdf.
Повний текст джерелаSenger, Anne Benedict. "A Study of DNA Replication and Repair Proteins from Bacteriophage T4 and a Related Phage." University of Toledo / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1104776177.
Повний текст джерелаBonne-Andrea, Catherine. "Contribution à l'étude des propriétés et du rôle biologique de la protéine non-histone HMG1." Paris 6, 1986. http://www.theses.fr/1986PA066451.
Повний текст джерелаCordonnier, Agnès. "Etude des mecanismes moleculaires de la replication de l'adn mitochondrial de xenopus laevis." Paris 6, 1987. http://www.theses.fr/1987PA066156.
Повний текст джерелаGharizadeh, Baback. "Method development and applications of Pyrosequencing technology." Doctoral thesis, KTH, Biotechnology, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3645.
Повний текст джерелаThe ability to determine nucleic acid sequences is one ofthe most important platforms for the detailed study ofbiological systems. Pyrosequencing technology is a relativelynovel DNA sequencing technique with multifaceted uniquecharacteristics, adjustable to different strategies, formatsand instrumentations. The aims of this thesis were to improvethe chemistry of the Pyrosequencing technique for increasedread-length, enhance the general sequence quality and improvethe sequencing performance for challenging templates. Improvedchemistry would enable Pyrosequencing technique to be used fornumerous applications with inherent advantages in accuracy,flexibility and parallel processing.
Pyrosequencing technology, at its advent, was restricted tosequencing short stretches of DNA. The major limiting factorwas presence of an isomer of dATPaS, a substitute for thenatural dATP, which inhibited enzyme activity in thePyrosequencing chemistry. By removing this non-functionalnucleotide, we were able to achieve DNA read-lengths of up toone hundred bases, which has been a substantial accomplishmentfor performance of different applications. Furthermore, the useof a new polymerase, called Sequenase, has enabled sequencingof homopolymeric T-regions, which are challenging for thetraditional Klenow polymerase. Sequenase has markedly madepossible sequencing of such templates with synchronizedextension.
The improved read-length and chemistry has enabledadditional applications, which were not possible previously.DNA sequencing is the gold standard method for microbial andvial typing. We have utilized Pyrosequencing technology foraccurate typing ofhuman papillomaviruses, and bacterial andfungal identification with promising results.
Furthermore, DNA sequencing technologies are not capable oftyping of a sample harboring a multitude of species/types orunspecific amplification products. We have addressed theproblem of multiple infections/variants present in a clinicalsample by a new versatile method. The multiple sequencingprimer method is suited for detection and typing of samplesharboring different clinically important types/species(multiple infections) and unspecific amplifications, whicheliminates the need for nested PCR, stringent PCR conditionsand cloning. Furthermore, the method has proved to be usefulfor samples containing subdominant types/species, and sampleswith low PCR yield, which avoids reperforming unsuccessfulPCRs. We also introduce the sequence pattern recognition whenthere is a plurality of genotypes in the sample, whichfacilitates typing of more than one target DNA in the sample.Moreover, target specific sequencing primers could be easilytailored and adapted according to the desired applications orclinical settings based on regional prevalence ofmicroorganisms and viruses.
Pyrosequencing technology has also been used forclone-checking by using preprogrammed nucleotide additionorder, EST sequencing and SNP analysis, yielding accurate andreliable results.
Keywords:apyrase, bacterial identification, dATPaS, ESTsequencing, fungal identification, human papillomavirus (HPV),microbial and viral typing, multiple sequencing primer method,Pyrosequencing technology, Sequenase, single-strandedDNA-binding protein (SSB), SNP analysis
Kaushal, Prem Singh. "Structural Studies Of Mycobacterial Uracil-DNA Glycosylase (Ung) And Single-Stranded DNA Binding Protein (SSB)." Thesis, 2010. https://etd.iisc.ac.in/handle/2005/1432.
Повний текст джерелаKaushal, Prem Singh. "Structural Studies Of Mycobacterial Uracil-DNA Glycosylase (Ung) And Single-Stranded DNA Binding Protein (SSB)." Thesis, 2010. http://etd.iisc.ernet.in/handle/2005/1432.
Повний текст джерелаHuang, Wen Hsin, and 黃文昕. "Molecular Cloning and Functional Characterization of single-stranded DNA binding protein (SSB, HP1245) from Helicobacter pylori." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/90698822259257219099.
Повний текст джерела國立清華大學
生物科技研究所
93
Single strand DNA binding protein (SSB) plays essential roles in many processes related to DNA metabolism such as DNA replication, repair, and homologous genetic recombination. The HP1245 gene was annotated as SSB in Helicobacter pylori strain 26695. However, there are no functional or structured studies for this SSB up to now. The full length (179 residues), three different C-terminal truncated species (106, 122 and 134 residues) and four different site directed mutants (F37A, F50A, F56A and W84A) were individually sub-cloned into pQE30 vector and expressed in E. coli SG13009. After IPTG induction, each species of recombinant (rec) HP1245 protein with N-terminally 6xHis-tagged fusion was purified by Ni-NTA affinity chromatography and its identity confirmed by mass spectrometry and Western blotting analysis using an anti-His-tag monoclonal antibody. Full length and various mutant recHP1245 proteins were homo-tetramer according to mass spectrometry and sedimentation velocity ultracentrifuge analysis, respectively. However, even in NaCl containing buffer, full length recHP1245 protein was easy to degrade after stored at 4℃ for 2 weeks, but C-terminal truncated proteins (122 and 134 residues) were stable for months. This indicated that the inherently disordered C-terminal region of SSB in H. pylori, similar to that in E. coli, may affect protein stability. The ssDNA binding property of HP1245 was performed through electrophoretic mobility shift assays (EMSA) to determine the binding affinity and the binding domain. The result indicated that the affinity of full-length or truncated recHP1245 proteins (122 and 134 residues) with biotin-labeled d(T)35 ssDNA was similar. It meant that the ssDNA binding domain was located at the N terminal. Furthermore, the site directed mutants, F37A, F50A, F56A and W84A were also individually measured by the same method. These results indicated that either F56A or W84A residue of recHP1245 protein would decrease the ssDNA binding affinity. Therefore, the two residues played a crucial role on ssDNA binding. These results suggested that the aromatic residues in this protein might contribute certain roles on ssDNA binding via base stacking interaction with the base in the ssDNA. In order to survive in stomach, Helicobacter pylori must have the ability to modify gene expression in acidic circumstances. To investigate whether HP1245 protein could be acid-induced or not at this stress, H. pylori were individually cultured on Brucella agar plates for 48 h at pH 7.0 and pH 5.5. In this study, the result showed that the protein expression of HP1245 did not have significant difference.
Singh, Amandeep. "Exploration of the Recombination Repair Pathway in Mycobacteria : Identification and Characterization of New Proteins." Thesis, 2018. https://etd.iisc.ac.in/handle/2005/4259.
Повний текст джерелаPadmakar, Purnapatre Kedar. "Uracil DNA Glycosylase From Mycobacteria And Escherichia coli : Mechanism Of Uracil Excision From Synthetic Substrates And Differential Interaction With Uracil DNA Glycosylase Inhibitor (Ugi) And Single Stranded DNA Binding Proteins (SSBs)." Thesis, 1999. https://etd.iisc.ac.in/handle/2005/1567.
Повний текст джерелаPadmakar, Purnapatre Kedar. "Uracil DNA Glycosylase From Mycobacteria And Escherichia coli : Mechanism Of Uracil Excision From Synthetic Substrates And Differential Interaction With Uracil DNA Glycosylase Inhibitor (Ugi) And Single Stranded DNA Binding Proteins (SSBs)." Thesis, 1999. http://etd.iisc.ernet.in/handle/2005/1567.
Повний текст джерелаSaikrishnan, K. "Structural Studies On Mycobacterial Proteins." Thesis, 2005. https://etd.iisc.ac.in/handle/2005/1496.
Повний текст джерелаSaikrishnan, K. "Structural Studies On Mycobacterial Proteins." Thesis, 2005. http://etd.iisc.ernet.in/handle/2005/1496.
Повний текст джерелаEggington, Julie M. "Deinococcus radiodurans single stranded DNA binding protein." 2006. http://www.library.wisc.edu/databases/connect/dissertations.html.
Повний текст джерелаLee, Yi-Juan, and 李易撰. "The ssDNA Binding Mode of Single-stranded DNA binding Protein from Helicobacter pylori." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/34606420981705800849.
Повний текст джерелаDombek, Priscilla Emily. "Functional domains of Agrobacterium tumefaciens single-stranded DNA binding protein VirE2." Thesis, 1996. http://hdl.handle.net/1957/34220.
Повний текст джерелаGraduation date: 1997
Chan, Kun-Wei, and 詹坤衛. "Structural Studies of Single-Stranded DNA Binding Protein from Helicobacter pylori." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/94826272919650941118.
Повний текст джерела國立清華大學
生物資訊與結構生物研究所
95
Abstract Single-stranded DNA binding protein (SSB) plays an important role in DNA metabolism, such as DNA replication, repair and recombination. The N-terminal domain of SSB forms an oligonucleotides/oligosaccharides binding (OB) fold, which function as single-stranded DNA (ssDNA) binding domain. The C-terminal conserved tail is supposed to participate in the protein-protein interaction. The crystal structure of C-terminal truncated SSB from Helicobacter pylori (residues 1-134, HpSSB134) bound to two dT(pT)34 [HpSSB134-dT(pT)34] was determined by molecular replacement method at 2.3 Å. The ssDNA wraps around four subunits of HpSSB134 by the electrostatic and hydrophobic stacking interactions. Four aromatic residues, Phe37, Phe50, Phe56 and Trp84, interact with the base of ssDNA by stacking arrangement. Meanwhile, four basic residues, Arg10, Arg36, Arg54 and Arg94, on the surface of HpSSB134 form a significant electrostatic path corresponding to the ssDNA binding.
Landt, Stephen George. "Arginine-rich motif peptides as tools for understanding single-stranded DNA recognition /." 2004. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3136068.
Повний текст джерелаChia-Hung, Wang. "Crystallographic Structural Studies of Single-Stranded DNA Binding Protein from Helicobacter pylori." 2006. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0016-1303200709300493.
Повний текст джерелаWang, Chia-Hung, and 王嘉宏. "Crystallographic Structural Studies of Single-Stranded DNA Binding Protein from Helicobacter pylori." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/98529896469303152233.
Повний текст джерела國立清華大學
生物資訊與結構生物研究所
94
Single-stranded DNA binding protein (SSB) plays an important role in DNA metabolism, such as DNA replication, repair, and recombination. SSB of Helicobacter pylori (HpSSB) is encoded by the ssb gene and contains 179 residues. The crystal structure of truncated HpSSB protein (residue 1-134) complexed with dT(pT)34 was determined at 3.1 resolution by X-ray crystallographic method. HpSSB exists as a tetramer in both crystal and solution states. The N-terminal domain (residue 1-115) contains an OB-fold (oligonucleotides binding fold), which is similar with other species like E. coli, to function as an ssDNA binding domain. However, the ssDNA binding mode of tmHpSSB134 exhibits a considerable variability with comparison to that of E. coli. In the structure of tmHpSSB134-dT(pT)34 complex, the ssDNA wraps on the OB-fold with mainly electrostatic and stacking interactions. Several basic residues, Arg10, Arg35, and Lsy108, on the surface of tmHpSSB134 form a significant patch to accommodate the ssDNA binding. Furthermore, two aromatic residues, Phe50 and Trp84, interact with thymidine by stacking interaction. The structure of residues 116-134 was unable to be determined because of its flexibility. Many evidences reveal that the acidic C-terminal tail of SSB might participate in the protein-protein interaction. The C-terminal interactions may trigger the activities of the associated proteins in DNA metabolism.
Szap, Matthew C. "Identification and characterization of a human single-stranded telomeric DNA binding protein /." Diss., 1997. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:9814991.
Повний текст джерелаKariawasam, Ruvini. "Determining the structural mechanism of how single-stranded DNA binding proteins bind DNA." Thesis, 2017. http://hdl.handle.net/1959.7/uws:47195.
Повний текст джерелаWebb, John R. "Cloning and characterization of a single-stranded DNA-binding protein of Leishmania major." Thesis, 1993. http://hdl.handle.net/2429/1899.
Повний текст джерелаSun, Siyang. "Biochemical and crystallographic studies of bacteriophage RB69 DNA polymerase and single-stranded DNA binding protein interactions." Thesis, 2006. http://hdl.handle.net/1911/18982.
Повний текст джерелаTouma, Christine. "Defining the mechanistic role of hSSB1 : a novel single-stranded DNA binding protein essential for DNA repair." Thesis, 2016. http://hdl.handle.net/1959.7/uws:41175.
Повний текст джерела黃禮堃. "Functional characterization of wild type and mutant single stranded DNA binding protein (HP1245) from H. pylori." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/74535860768245069895.
Повний текст джерела國立清華大學
生物科技研究所
97
Single stranded DNA (ssDNA) binding protein (SSB) plays essential roles in many processes related to DNA metabolism such as DNA replication, repair, and homologous genetic recombination. The HP1245 gene was annotated as SSB in Helicobacter pylori strain 26695. However, there are no functional or structured studies for this SSB up to now. The full length (179 residues) HP1245, a C-terminal truncated HP1245 containing 134 resides (tmHP1245 (1~134)), and four HP1245 mutants each containing 134 residues with a specific site mutant (F37A, F50A, F56A and W84A) were individually cloned into pQE30 vector and expressed in E. coli SG13009 previously in our lab. Applied basic gene cloning techniques and available plasmids, the gene containing full length HP1245 SSB with a point mutation on F37A, F50A, F56A or W84A was separately constructed and expressed in pQE30 containing E. coli SG13009 system. In addition, EcoSSB containing expression vector in E. coli SG13009 system was also prepared in this study. The binding activity between single stranded DNA and any one of the above mentioned fresh prepared HP1245 proteins (full length wild type, full length point mutants and C-terminal truncated mutant) were measured by means of (a) fluorescence titration (fixed amount of SSB plus fragmented calf thymus ss-DNA, or 600-1200 bp), (b) Electrophoresis mobility shift assay (EMSA) (SSB plus fixed amount of M13mp18 ssDNA) and (c) SPR (biotin-labeled d(T)35 ssDNA) in this study. The results of the fluorescence titration from the measurement of the tryptophan quenching due to the ssDNA binding to SSB provided one useful parameter, binding site sizes of nucleotides or Napp to wrap around (or cover) a SSB tetramer. Under high salt condition at 300 mM NaCl, the Napp for the full length HP1245 SSB was 35 + 2 nucleotides/tetramer, shorter than that for EcoSSB (61 + 4 NT/tetramer). The tmHP1245 owned the shortest Napp (30 + 1 NT/tetramer) among the various HP1245 SSB mutants used in this study. Similar results were also observed from SSB binding to ssDNA at low salt 10 mM NaCl condition, suggesting that the C-terminal of HP1245 SSB should play a role on ssDNA binding. On the other hand, EMSA results on retardation of the single stranded M13mp18 plasmid DNA migration on DNA agarose gel during SSB binding showed that about 330~439 molecules of full length HP1245 tetramer would saturate to bind one molecule of M13mp18 at high or low salt. Strong positive co-operativity showed in wild type HP1245 SSB-M13 complexes only at low salt condition. More tm-HP1245 tetramers were required to saturate the binding of single M13 molecule, indicating the C-terminal region of HP1245 affected the retardation of EMSA. The interaction of a series SSB with ssDNA has been further measured in real time by using a surface plasmon-resonance (SPR) and biosensor chip. Wild type HP1245 SSB was first applied onto the sensor chip surface that was pre-coated with Au, MUA, EDC/NHS, Streptoavidin and 5’-Biotinyl-poly(dT)35 in order. SPR measure at different conditions including: strpetavidin immobilization buffer pH value (Figure 11), 5’ biotinyl-poly(dT)35 capacity (Figure 12), flow rate of kinetic experiments (Figure13), regeneration buffer (Figure 14), HP1245 protein concentration and association time (Figure 16) were examined to obtain optimal conditions for further DNA binding experiments for each of above mentioned various HP1245 SSB. Response unit (RU) data from SPR after processing software program, BIAevaluation version 4.1 were transformed into useful parameters, such as ka, kd, KA, KD etc. to describe the SSB and ssDNA binding affinity. The KD of wild type HP1245 SSB binding poly dT 35mer was 0.16 nM in using BiacoreX (Figure 16A) and 0.1 nM in using Biacore3000 (Figure 16B), although different association time was used, 2 min for the former and 5 min for the latter. Higher KD (1.64 nM, about 9.9-fold, Figure 18) was obtained for C-terminal tm-HP1245 (1~134) in comparison with that from full-length HP1245 SSB to bind ssDNA. This result again emphasized that C-terminal of HP1245 was important for ssDNA binding. The importance of the C-terminal region on HP1245 was confirmed in results from fluorescence titration, EMSA and SPR measurement in this study. KD value for the binding of SSB to ssDNA from the lowest to highest is 0.16 nM for full length wild type HP1245 SSB, 1.6 nM (10-fold) for F37A mutant (Figure 19), 1.64 nM (10-fold) for tm-HP1245 (1~134) (Figure 18), 2.3 nM (14.1-fold) for W84A mutant (Figure 19), 3.06 nM (18.4-fold) for F50A mutant (Figure 19) and 3.12 nM (18.6-fold) for F56A mutant (Figure 20). These results suggested that the mutation of F37, F50, F56 or W84 in HP1245 SSB affected its binding to ssDNA, resulting in less KA (more binding affinity between SSB and ssDNA) or more KD (less dissociation for SSB-ssDNA complex) than that for wild type HP1245 SSB. Thus, SPR analysis was the most convenient method to examine the binding between ssDNA and different HP1245 SSB. It demonstrated that HP1245 SSB binds single stranded DNA with high affinity, by involving a tryptophan residue W84, and 3 phenylalanines F37, F50 and F56. Either SPR, fluorescence titration or EMSA could be used to distinguish different KD between tm-HP1245 SSB and wild type HP1245 SSB for ssDNA binding, higher KD (10-fold) in the former than that in the latter. This confirmed that the C-terminal region of HP1245 SSB was also important to bind ssDNA.
Eggler, Aimee Laura. "Dissecting the inhibitory and stimulating effects of single-stranded DNA binding proteins on the activities of saccharomyces cerevisiae Rad51 protein and escherichia coli RecA protein." 2002. http://www.library.wisc.edu/databases/connect/dissertations.html.
Повний текст джерелаBarrientos, KS, MF Kendellen, BD Freibaum, BN Armbruster, KT Etheridge, and CM Counter. "Distinct functions of POT1 at telomeres." Thesis, 2008. http://hdl.handle.net/10161/1343.
Повний текст джерелаDissertation
Cappadocia, Laurent. "Étude structurale du mode de liaison des protéines Whirly de plantes à l’ADN monocaténaire." Thèse, 2010. http://hdl.handle.net/1866/4957.
Повний текст джерелаPlants must protect the integrity of three genomes located respectively in the nucleus, the chloroplasts and the mitochondria. Although DNA repair mechanisms in the nucleus are the subject of multiple studies, little attention has been paid to DNA repair mechanisms in chloroplasts and mitochondria. This is unfortunate since mutations in the chloroplast or the mitochondrial genome can lead to altered plant growth and development. Our laboratory has identified a new family of proteins, the Whirlies, whose members are located in plant mitochondria and chloroplasts. These proteins form tetramers that bind single-stranded DNA and play various roles associated with DNA metabolism. In Arabidopsis, two Whirly proteins maintain chloroplast genome stability. Whether or not these proteins are involved in DNA repair has so far not been investigated. Our studies in Arabidopsis demonstrate that DNA double-strand breaks are repaired in both mitochondria and chloroplasts through a microhomology-mediated repair pathway and indicate that Whirly proteins affect this pathway. In particular, the role of Whirly proteins would be to promote accurate repair of organelle DNA by preventing the repair of DNA double-strand breaks by the microhomology-dependant pathway. To understand how Whirly proteins mediate this function, we solved the crystal structure of Whirly-DNA complexes. These structures show that Whirly proteins bind single-stranded DNA with low sequence specificity. The DNA is maintained in an extended conformation between the β-sheets of adjacent protomers, thus preventing spurious annealing with a complementary strand. In turn, this prevents formation of DNA rearrangements and favors accurate DNA repair. We also show that upon binding long ssDNA sequences, Whirly proteins assemble into higher order structures, or hexamers of tetramers, thus forming spherical particles of twelve nanometers in diameter. We also demonstrate that a lysine residue conserved among plant Whirly proteins is important for the stability of these higher order structures as well as for cooperative binding to DNA and for DNA repair. Overall, our study elucidates some of the mechanisms of DNA repair in plant organelles as well as the roles of Whirly proteins in this process.