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Pallara C, Jiménez-García B, Romero M, Moal IH, Fernández-Recio J. pyDock scoring for the new modeling challenges in docking: Protein-peptide, homo-multimers, and domain-domain interactions. Proteins 2016; 85:487-496. [PMID: 27701776 DOI: 10.1002/prot.25184] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 09/22/2016] [Accepted: 10/02/2016] [Indexed: 12/18/2022]
Abstract
The sixth CAPRI edition included new modeling challenges, such as the prediction of protein-peptide complexes, and the modeling of homo-oligomers and domain-domain interactions as part of the first joint CASP-CAPRI experiment. Other non-standard targets included the prediction of interfacial water positions and the modeling of the interactions between proteins and nucleic acids. We have participated in all proposed targets of this CAPRI edition both as predictors and as scorers, with new protocols to efficiently use our docking and scoring scheme pyDock in a large variety of scenarios. In addition, we have participated for the first time in the servers section, with our recently developed webserver, pyDockWeb. Excluding the CASP-CAPRI cases, we submitted acceptable models (or better) for 7 out of the 18 evaluated targets as predictors, 4 out of the 11 targets as scorers, and 6 out of the 18 targets as servers. The overall success rates were below those in past CAPRI editions. This shows the challenging nature of this last edition, with many difficult targets for which no participant submitted a single acceptable model. Interestingly, we submitted acceptable models for 83% of the evaluated protein-peptide targets. As for the 25 cases of the CASP-CAPRI experiment, in which we used a larger variety of modeling techniques (template-based, symmetry restraints, literature information, etc.), we submitted acceptable models for 56% of the targets. In summary, this CAPRI edition showed that pyDock scheme can be efficiently adapted to the increasing variety of problems that the protein interactions field is currently facing. Proteins 2017; 85:487-496. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Chiara Pallara
- Life Sciences Department, Joint BSC-CRG-IRB Research Program in Computational Biology, Barcelona Supercomputing Center, Barcelona, Spain
| | - Brian Jiménez-García
- Life Sciences Department, Joint BSC-CRG-IRB Research Program in Computational Biology, Barcelona Supercomputing Center, Barcelona, Spain
| | - Miguel Romero
- Life Sciences Department, Joint BSC-CRG-IRB Research Program in Computational Biology, Barcelona Supercomputing Center, Barcelona, Spain
| | - Iain H Moal
- Life Sciences Department, Joint BSC-CRG-IRB Research Program in Computational Biology, Barcelona Supercomputing Center, Barcelona, Spain.,European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SD, United Kingdom
| | - Juan Fernández-Recio
- Life Sciences Department, Joint BSC-CRG-IRB Research Program in Computational Biology, Barcelona Supercomputing Center, Barcelona, Spain
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52
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Wang Y, Gan N, Zhou Y, Li T, Cao Y, Chen Y. Novel single-stranded DNA binding protein-assisted fluorescence aptamer switch based on FRET for homogeneous detection of antibiotics. Biosens Bioelectron 2016; 87:508-513. [PMID: 27596250 DOI: 10.1016/j.bios.2016.08.107] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 08/08/2016] [Accepted: 08/30/2016] [Indexed: 01/08/2023]
Abstract
Herein, a smart single-stranded DNA binding protein (SSB)-assisted fluorescence aptamer switch based on fluorescence resonance energy transfer (FRET) was designed. The FRET switch was synthesized by connecting SSB labeled quantum dots (QDs@SSB) as donor with aptamer (apt) labeled gold nanoparticles (AuNPs@apt) as acceptor, and it was employed for detecting chloramphenicol (CAP) in a homogenous solution. In the assay, the interaction between core-shell QDs@SSB and AuNPs@apt leads to a dramatic quenching (turning off). After adding CAP in the detection system, AuNPs@apt can bind the target specifically then separate QDs@SSB with AuNPs@apt-target, resulting in restoring the fluorescence intensity of QDs (turning on). Consequently, the fluorescence intensity recovers and the recovery extent can be used for detection of CAP in homogenous phase via optical responses. Under optimal conditions, the fluorescence intensity increased linearly with increasing concentrations of CAP from 0.005 to 100ngmL-1. The limit of this fluorescence aptamer switch was around 3pgmL-1 for CAP detection. When the analyte is changed, the assay can be applied to detect other targets only by changing relative aptamer in AuNPs@apt probe. Furthermore, it has potential to be served as a simple, sensitive and portable platform for antibiotic contaminants detection in biological and environmental samples.
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Affiliation(s)
- Ye Wang
- Faculty of Material Science and Chemical Engineering, Ningbo University, Ningbo 315211, China
| | - Ning Gan
- Faculty of Material Science and Chemical Engineering, Ningbo University, Ningbo 315211, China.
| | - You Zhou
- Faculty of Material Science and Chemical Engineering, Ningbo University, Ningbo 315211, China
| | - Tianhua Li
- Faculty of Material Science and Chemical Engineering, Ningbo University, Ningbo 315211, China
| | - Yuting Cao
- Faculty of Material Science and Chemical Engineering, Ningbo University, Ningbo 315211, China
| | - Yinji Chen
- Deptartment of Food Science and Engineering/Collaborative Innovation Center for Modern Grain Circulation and Safety, Nanjing University of Finance and Economics, Nanjing 210000, China
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Chen SH, Byrne-Nash RT, Cox MM. Escherichia coli RadD Protein Functionally Interacts with the Single-stranded DNA-binding Protein. J Biol Chem 2016; 291:20779-86. [PMID: 27519413 DOI: 10.1074/jbc.m116.736223] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Indexed: 11/06/2022] Open
Abstract
The bacterial single-stranded DNA binding protein (SSB) acts as an organizer of DNA repair complexes. The radD gene was recently identified as having an unspecified role in repair of radiation damage and, more specifically, DNA double-strand breaks. Purified RadD protein displays a DNA-independent ATPase activity. However, ATP hydrolytic rates are stimulated by SSB through its C terminus. The RadD and SSB proteins also directly interact in vivo in a yeast two-hybrid assay and in vitro through ammonium sulfate co-precipitation. Therefore, it is likely that the repair function of RadD is mediated through interaction with SSB at the site of damage.
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Affiliation(s)
- Stefanie H Chen
- From the Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Rose T Byrne-Nash
- From the Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Michael M Cox
- From the Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706
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54
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Wessel SR, Cornilescu CC, Cornilescu G, Metz A, Leroux M, Hu K, Sandler SJ, Markley JL, Keck JL. Structure and Function of the PriC DNA Replication Restart Protein. J Biol Chem 2016; 291:18384-96. [PMID: 27382050 DOI: 10.1074/jbc.m116.738781] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Indexed: 11/06/2022] Open
Abstract
Collisions between DNA replication complexes (replisomes) and barriers such as damaged DNA or tightly bound protein complexes can dissociate replisomes from chromosomes prematurely. Replisomes must be reloaded under these circumstances to avoid incomplete replication and cell death. Bacteria have evolved multiple pathways that initiate DNA replication restart by recognizing and remodeling abandoned replication forks and reloading the replicative helicase. In vitro, the simplest of these pathways is mediated by the single-domain PriC protein, which, along with the DnaC helicase loader, can load the DnaB replicative helicase onto DNA bound by the single-stranded DNA (ssDNA)-binding protein (SSB). Previous biochemical studies have identified PriC residues that mediate interactions with ssDNA and SSB. However, the mechanisms by which PriC drives DNA replication restart have remained poorly defined due to the limited structural information available for PriC. Here, we report the NMR structure of full-length PriC from Cronobacter sakazakii PriC forms a compact bundle of α-helices that brings together residues involved in ssDNA and SSB binding at adjacent sites on the protein surface. Disruption of these interaction sites and of other conserved residues leads to decreased DnaB helicase loading onto SSB-bound DNA. We also demonstrate that PriC can directly interact with DnaB and the DnaB·DnaC complex. These data lead to a model in which PriC acts as a scaffold for recruiting DnaB·DnaC to SSB/ssDNA sites present at stalled replication forks.
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Affiliation(s)
- Sarah R Wessel
- From the Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706
| | - Claudia C Cornilescu
- the National Magnetic Resonance Facility at Madison and the Biochemistry Department, University of Wisconsin, Madison, Wisconsin 53706, and
| | - Gabriel Cornilescu
- the National Magnetic Resonance Facility at Madison and the Biochemistry Department, University of Wisconsin, Madison, Wisconsin 53706, and
| | - Alice Metz
- the Department of Microbiology, University of Massachusetts, Amherst, Massachusetts 01003
| | - Maxime Leroux
- the Department of Microbiology, University of Massachusetts, Amherst, Massachusetts 01003
| | - Kaifeng Hu
- the National Magnetic Resonance Facility at Madison and the Biochemistry Department, University of Wisconsin, Madison, Wisconsin 53706, and
| | - Steven J Sandler
- the Department of Microbiology, University of Massachusetts, Amherst, Massachusetts 01003
| | - John L Markley
- the National Magnetic Resonance Facility at Madison and the Biochemistry Department, University of Wisconsin, Madison, Wisconsin 53706, and
| | - James L Keck
- From the Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706,
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55
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Cheng K, Xu H, Chen X, Wang L, Tian B, Zhao Y, Hua Y. Structural basis for DNA 5´-end resection by RecJ. eLife 2016; 5:e14294. [PMID: 27058167 PMCID: PMC4846377 DOI: 10.7554/elife.14294] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 04/07/2016] [Indexed: 12/18/2022] Open
Abstract
The resection of DNA strand with a 5´ end at double-strand breaks is an essential step in recombinational DNA repair. RecJ, a member of DHH family proteins, is the only 5´ nuclease involved in the RecF recombination pathway. Here, we report the crystal structures of Deinococcus radiodurans RecJ in complex with deoxythymidine monophosphate (dTMP), ssDNA, the C-terminal region of single-stranded DNA-binding protein (SSB-Ct) and a mechanistic insight into the RecF pathway. A terminal 5´-phosphate-binding pocket above the active site determines the 5´-3´ polarity of the deoxy-exonuclease of RecJ; a helical gateway at the entrance to the active site admits ssDNA only; and the continuous stacking interactions between protein and nine nucleotides ensure the processive end resection. The active site of RecJ in the N-terminal domain contains two divalent cations that coordinate the nucleophilic water. The ssDNA makes a 180° turn at the scissile phosphate. The C-terminal domain of RecJ binds the SSB-Ct, which explains how RecJ and SSB work together to efficiently process broken DNA ends for homologous recombination.
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Affiliation(s)
- Kaiying Cheng
- Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China
| | - Hong Xu
- Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China
| | - Xuanyi Chen
- Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China
| | - Liangyan Wang
- Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China
| | - Bing Tian
- Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China
| | - Ye Zhao
- Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China
| | - Yuejin Hua
- Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China
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Vidhyasagar V, He Y, Guo M, Ding H, Talwar T, Nguyen V, Nwosu J, Katselis G, Wu Y. C-termini are essential and distinct for nucleic acid binding of human NABP1 and NABP2. Biochim Biophys Acta Gen Subj 2015; 1860:371-83. [PMID: 26550690 DOI: 10.1016/j.bbagen.2015.11.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 10/30/2015] [Accepted: 11/04/2015] [Indexed: 01/03/2023]
Abstract
BACKGROUND Human Nucleic Acid Binding Protein 1 and 2 (hNABP1 and 2; also known as hSSB2 and 1, respectively) are two newly identified single-stranded (ss) DNA binding proteins (SSB). Both NABP1 and NABP2 have a conserved oligonucleotide/oligosaccharide-binding (OB)-fold domain and a divergent carboxy-terminal domain, the functional importance of which is unknown. METHODS Recombinant hNABP1/2 proteins were purified using affinity and size exclusion chromatography and their identities confirmed by mass spectrometry. Oligomerization state was checked by sucrose gradient centrifugation. Secondary structure was determined by circular dichroism spectroscopy. Nucleic acid binding ability was examined by EMSA and ITC. RESULTS Both hNABP1 and hNABP2 exist as monomers in solution; however, hNABP2 exhibits anomalous behavior. CD spectroscopy revealed that the C-terminus of hNABP2 is highly disordered. Deletion of the C-terminal tail diminishes the DNA binding ability and protein stability of hNABP2. Although both hNABP1 and hNABP2 prefer to bind ssDNA than double-stranded (ds) DNA, hNABP1 has a higher affinity for ssDNA than hNABP2. Unlike hNABP2, hNABP1 protein binds and multimerizes on ssDNA with the C-terminal tail responsible for its multimerization. Both hNABP1 and hNABP2 are able to bind single-stranded RNA, with hNABP2 having a higher affinity than hNABP1. CONCLUSIONS Biochemical evidence suggests that the C-terminal region of NABP1 and NABP2 is essential for their functionality and may lead to different roles in DNA and RNA metabolism. GENERAL SIGNIFICANCE This is the first report demonstrating the regulation and functional properties of the C-terminal domain of hNABP1/2, which might be a general characteristic of OB-fold proteins.
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Affiliation(s)
- Venkatasubramanian Vidhyasagar
- Department of Biochemistry, University of Saskatchewan, Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Yujiong He
- Department of Biochemistry, University of Saskatchewan, Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Manhong Guo
- Department of Biochemistry, University of Saskatchewan, Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Hao Ding
- Department of Biochemistry, University of Saskatchewan, Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Tanu Talwar
- Department of Biochemistry, University of Saskatchewan, Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Vi Nguyen
- Department of Biochemistry, University of Saskatchewan, Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Jessica Nwosu
- Department of Biochemistry, University of Saskatchewan, Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - George Katselis
- Department of Medicine, University of Saskatchewan, Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada; Canadian Centre for Health and Safety in Agriculture, University of Saskatchewan, Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Yuliang Wu
- Department of Biochemistry, University of Saskatchewan, Health Sciences Building, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada.
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57
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Bell JC, Liu B, Kowalczykowski SC. Imaging and energetics of single SSB-ssDNA molecules reveal intramolecular condensation and insight into RecOR function. eLife 2015; 4:e08646. [PMID: 26381353 PMCID: PMC4652220 DOI: 10.7554/elife.08646] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 09/18/2015] [Indexed: 11/13/2022] Open
Abstract
Escherichia coli single-stranded DNA (ssDNA) binding protein (SSB) is the defining bacterial member of ssDNA binding proteins essential for DNA maintenance. SSB binds ssDNA with a variable footprint of ∼30-70 nucleotides, reflecting partial or full wrapping of ssDNA around a tetramer of SSB. We directly imaged single molecules of SSB-coated ssDNA using total internal reflection fluorescence (TIRF) microscopy and observed intramolecular condensation of nucleoprotein complexes exceeding expectations based on simple wrapping transitions. We further examined this unexpected property by single-molecule force spectroscopy using magnetic tweezers. In conditions favoring complete wrapping, SSB engages in long-range reversible intramolecular interactions resulting in condensation of the SSB-ssDNA complex. RecO and RecOR, which interact with SSB, further condensed the complex. Our data support the idea that RecOR--and possibly other SSB-interacting proteins-function(s) in part to alter long-range, macroscopic interactions between or throughout nucleoprotein complexes by microscopically altering wrapping and bridging distant sites.
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Affiliation(s)
- Jason C Bell
- Graduate Group in Biochemistry and Molecular Biology, University of California, Davis, Davis, United States
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, United States
| | - Bian Liu
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, United States
- Graduate Group in Biophysics, University of California, Davis, Davis, United States
| | - Stephen C Kowalczykowski
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, United States
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