scholarly journals Mcm10 has potent strand-annealing activity and limits translocase-mediated fork regression

2018 ◽  
Vol 116 (3) ◽  
pp. 798-803 ◽  
Author(s):  
Ryan Mayle ◽  
Lance Langston ◽  
Kelly R. Molloy ◽  
Dan Zhang ◽  
Brian T. Chait ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Cross Linking ◽  
Replication Forks ◽  
Binding Region ◽  
Replicative Helicase ◽  
Template Analysis ◽  
Dna Translocases ◽  
Fork Regression ◽  
Strand Annealing

The 11-subunit eukaryotic replicative helicase CMG (Cdc45, Mcm2-7, GINS) tightly binds Mcm10, an essential replication protein in all eukaryotes. Here we show that Mcm10 has a potent strand-annealing activity both alone and in complex with CMG. CMG-Mcm10 unwinds and then reanneals single strands soon after they have been unwound in vitro. Given the DNA damage and replisome instability associated with loss of Mcm10 function, we examined the effect of Mcm10 on fork regression. Fork regression requires the unwinding and pairing of newly synthesized strands, performed by a specialized class of ATP-dependent DNA translocases. We show here that Mcm10 inhibits fork regression by the well-known fork reversal enzyme SMARCAL1. We propose that Mcm10 inhibits the unwinding of nascent strands to prevent fork regression at normal unperturbed replication forks, either by binding the fork junction to form a block to SMARCAL1 or by reannealing unwound nascent strands to their parental template. Analysis of the CMG-Mcm10 complex by cross-linking mass spectrometry reveals Mcm10 interacts with six CMG subunits, with the DNA-binding region of Mcm10 on the N-face of CMG. This position on CMG places Mcm10 at the fork junction, consistent with a role in regulating fork regression.

scholarly journals RuvAB and RecG Are Not Essential for the Recovery of DNA Synthesis Following UV-Induced DNA Damage in Escherichia coli

Genetics ◽  
2004 ◽  
Vol 166 (4) ◽  
pp. 1631-1640 ◽  
Author(s):  
Janet R Donaldson ◽  
Charmain T Courcelle ◽  
Justin Courcelle
Keyword(s):  
Dna Damage ◽  
Dna Synthesis ◽  
Dna Lesions ◽  
Replication Forks ◽  
Wild Type ◽  
Replication Machinery ◽  
Dna Junctions ◽  
Fork Regression

Abstract Ultraviolet light induces DNA lesions that block the progression of the replication machinery. Several models speculate that the resumption of replication following disruption by UV-induced DNA damage requires regression of the nascent DNA or migration of the replication machinery away from the blocking lesion to allow repair or bypass of the lesion to occur. Both RuvAB and RecG catalyze branch migration of three- and four-stranded DNA junctions in vitro and are proposed to catalyze fork regression in vivo. To examine this possibility, we characterized the recovery of DNA synthesis in ruvAB and recG mutants. We found that in the absence of either RecG or RuvAB, arrested replication forks are maintained and DNA synthesis is resumed with kinetics that are similar to those in wild-type cells. The data presented here indicate that RecG- or RuvAB-catalyzed fork regression is not essential for DNA synthesis to resume following arrest by UV-induced DNA damage in vivo.

Chemical Cross-Linking/Mass Spectrometry Maps the Amyloid β Peptide Binding Region on Both Apolipoprotein E Domains

2015 ◽  
Vol 10 (4) ◽  
pp. 1010-1016 ◽  
Author(s):  
Stéphanie Deroo ◽  
Florian Stengel ◽  
Azadeh Mohammadi ◽  
Nicolas Henry ◽  
Ellen Hubin ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Apolipoprotein E ◽  
Peptide Binding ◽  
Amyloid Β ◽  
Cross Linking ◽  
Amyloid Β Peptide ◽  
Binding Region ◽  
Peptide Binding Region ◽  
Chemical Cross Linking

scholarly journals UvrD Participation in Nucleotide Excision Repair Is Required for the Recovery of DNA Synthesis following UV-Induced Damage inEscherichia coli

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Kelley N. Newton ◽  
Charmain T. Courcelle ◽  
Justin Courcelle
Keyword(s):  
Dna Damage ◽  
Dna Synthesis ◽  
Nucleotide Excision Repair ◽  
Excision Repair ◽  
Dna Helicase ◽  
Replication Forks ◽  
Nucleotide Excision ◽  
Fork Regression

UvrD is a DNA helicase that participates in nucleotide excision repair and several replication-associated processes, including methyl-directed mismatch repair and recombination. UvrD is capable of displacing oligonucleotides from synthetic forked DNA structuresin vitroand is essential for viability in the absence of Rep, a helicase associated with processing replication forks. These observations have led others to propose that UvrD may promote fork regression and facilitate resetting of the replication fork following arrest. However, the molecular activity of UvrD at replication forksin vivohas not been directly examined. In this study, we characterized the role UvrD has in processing and restoring replication forks following arrest by UV-induced DNA damage. We show that UvrD is required for DNA synthesis to recover. However, in the absence of UvrD, the displacement and partial degradation of the nascent DNA at the arrested fork occur normally. In addition, damage-induced replication intermediates persist and accumulate inuvrDmutants in a manner that is similar to that observed in other nucleotide excision repair mutants. These data indicate that, following arrest by DNA damage, UvrD is not required to catalyze fork regressionin vivoand suggest that the failure ofuvrDmutants to restore DNA synthesis following UV-induced arrest relates to its role in nucleotide excision repair.

scholarly journals Intrinsic Degradation of the Type-II Antitoxin ParD from Pseudomonas aeruginosa

2021 ◽  
Author(s):  
Kevin J. Snead ◽  
Christina R. Bourne
Keyword(s):  
Mass Spectrometry ◽  
Pseudomonas Aeruginosa ◽  
Secreted Proteins ◽  
Type Ii ◽  
Direct Infusion ◽  
Binding Region ◽  
Toxin Binding ◽  
Direct Infusion Mass Spectrometry ◽  
Intrinsic Degradation

AbstractType-II Toxin Antitoxin (TA) systems are regulated by differential half-lives of the resulting non-secreted proteins, such that the neutralizing antitoxin undergoes continual degradation and replenishment to maintain neutralization of its cognate toxin. Antitoxin proteins are widely reported as labile, including upon purification and in vitro storage. During the course of studies on a ParDE TA system we noted a prevalent in vitro degradation of the ParD antitoxin. In efforts to combat this for practical use in assays, we characterized parameters impacting the degradation as well as the resulting products. These revealed a mechanism likely mediated by a serine or metal-dependent protease. Using Direct Infusion Mass Spectrometry, the cleavage products were identified as an essentially intact DNA binding region of the antitoxin and with the toxin binding domain completely removed. No other species were identified in the solution, such as a contaminant that may mediate such cleavage. Therefore, while our studies revealed viable strategies to mitigate the in vitro degradation they did not identify any protease, leaving open the possibility of a potential auto-catalytic proteolytic activity of the antitoxin proteins.

scholarly journals Cross-linking/Mass Spectrometry: A Community-Wide, Comparative Study Towards Establishing Best Practice Guidelines

2018 ◽  
Author(s):  
Claudio Iacobucci ◽  
Christine Piotrowski ◽  
Ruedi Aebersold ◽  
Bruno C. Amaral ◽  
Philip Andrews ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Data Analysis ◽  
Practice Guidelines ◽  
Protein Interactions ◽  
Best Practice ◽  
Dimensional Structure ◽  
Cross Linking ◽  
Best Practice Guidelines

AbstractThe number of publications in the field of chemical cross-linking combined with mass spectrometry (XL-MS) to derive constraints for protein three-dimensional structure modeling and to probe protein-protein interactions has largely increased during the last years. As the technique is now becoming routine for in vitro and in vivo applications in proteomics and structural biology there is a pressing need to define protocols as well as data analysis and reporting formats that are generally accepted in the field and that have shown to lead to high-quality results. This first, community-based harmonization study on XL-MS is based on the results of 32 groups participating worldwide. The aim of this paper is to summarize the status quo of XL-MS and to compare and evaluate existing cross-linking strategies. From the results obtained, common protocols will be established. Our study serves as basis for establishing best practice guidelines in the field for conducting cross-linking experiments, performing data analysis, and reporting formats with the ultimate goal of assisting scientists to generate accurate and reproducible XL-MS results.

scholarly journals Mapping the native interaction surfaces of PREP1 with PBX1 by cross-linking mass-spectrometry and mutagenesis

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Chiara Bruckmann ◽  
Simone Tamburri ◽  
Valentina De Lorenzi ◽  
Nunzianna Doti ◽  
Alessandra Monti ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Binding Sites ◽  
Transcriptional Activity ◽  
Tertiary Structure ◽  
Cross Linking ◽  
Interaction Sites ◽  
First Time

Abstract Both onco-suppressor PREP1 and the oncogene MEIS1 bind to PBX1. This interaction stabilizes the two proteins and allows their translocation into the nucleus and thus their transcriptional activity. Here, we have combined cross-linking mass-spectrometry and systematic mutagenesis to detail the binding geometry of the PBX1-PREP1 (and PBX1-MEIS1) complexes, under native in vivo conditions. The data confirm the existence of two distinct interaction sites within the PBC domain of PBX1 and unravel differences among the highly similar binding sites of MEIS1 and PREP1. The HR2 domain has a fundamental role in binding the PBC-B domain of PBX1 in both PREP1 and MEIS1. The HR1 domain of MEIS1, however, seem to play a less stringent role in PBX1 interaction with respect to that of PREP1. This difference is also reflected by the different binding affinity of the two proteins to PBX1. Although partial, this analysis provides for the first time some ideas on the tertiary structure of the complexes not available before. Moreover, the extensive mutagenic analysis of PREP1 identifies the role of individual hydrophobic HR1 and HR2 residues, both in vitro and in vivo.

scholarly journals A Weak Spliceosome-Binding Domain of Yju2 Functions in the First Step and Bypasses Prp16 in the Second Step of Splicing

2013 ◽  
Vol 33 (9) ◽  
pp. 1746-1755 ◽  
Author(s):  
Ting-Wei Chiang ◽  
Soo-Chen Cheng
Keyword(s):  
Branch Point ◽  
Binding Domain ◽  
Splicing Factor ◽  
Second Step ◽  
Cross Linking ◽  
Binding Region ◽  
U2 Snrna ◽  
Low Level

Yju2 is an essential splicing factor required for the first catalytic step after the action of Prp2. We dissected the structure of Yju2 and found that the amino (Yju2-N) and carboxyl (Yju2-C) halves of the protein can be separated and reconstituted for Yju2 function both in vivo and in vitro . Yju2-N has a weak affinity for the spliceosome but functions in promoting the first reaction, with the second reaction being severely impeded. The association of Yju2-N with the spliceosome is stabilized by the presence of Yju2-C at both the precatalytic and postcatalytic stages. Strikingly, Yju2-N supported a low level of the second reaction even in the absence of Prp16. Prp16 is known to mediate destabilization of Yju2 and Cwc25 after the first reaction to allow progression of the second reaction. We propose that in the absence of the C domain, Yju2-N is not stably associated with the spliceosome after lariat formation, and thus bypasses the need for Prp16. We also showed, by UV cross-linking, that Yju2 directly contacts U2 snRNA primarily in the helix II region both pre- and postcatalytically and in the branch-binding region only at the precatalytic stage, suggesting a possible role for Yju2 in positioning the branch point during the first reaction.

Localization of a Vitronectin Binding Region of Plasminogen Activator Inhibitor-1

1995 ◽  
Vol 73 (05) ◽  
pp. 829-834 ◽  
Author(s):  
Jaya Padmanabhan ◽  
David C Sane
Keyword(s):  
Binding Site ◽  
Plasminogen Activator ◽  
Inhibitory Activity ◽  
Plasminogen Activator Inhibitor ◽  
Structural Homology ◽  
Binding Region ◽  
Plasminogen Activator Inhibitor 1 ◽  
Activator Inhibitor ◽  
Pai 1

SummaryThe PAI-1 binding site for VN was studied using two independent methods. PAI-1 was cleaved by Staph V8 protease, producing 8 fragments, only 2 of which bound to [125I]-VN. These fragments were predicted to overlap between residues 91-130. Since PAI-2 has structural homology to PAI-1, but does not bind to vitronectin, chimeras of PAI-1 and PAI-2 were constructed. Four chimeras, containing PAI-1 residues 1-70,1-105,1-114, and 1-167 were constructed and expressed in vitro. PAI-1, PAI-2, and all of the chimeras retained inhibitory activity for t-PA, but only the chimera containing PAI-1 residues 1-167 formed a complex with VN. Together, these results predict that the VN binding site of PAI-1 is between residues 115-130.

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