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Tian Z, Li X, Li M, Wu W, Zhang M, Tang C, Li Z, Liu Y, Chen Z, Yang M, Ma L, Caba C, Tong Y, Lam HM, Dai S, Chen Z. Crystal structures of REF6 and its complex with DNA reveal diverse recognition mechanisms. Cell Discov 2020; 6:17. [PMID: 32257379 PMCID: PMC7105484 DOI: 10.1038/s41421-020-0150-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 02/03/2020] [Indexed: 12/12/2022] Open
Abstract
Relative of Early Flowing 6 (REF6) is a DNA-sequence-specific H3K27me3/2 demethylase that contains four zinc finger (ZnF) domains and targets several thousand genes in Arabidopsis thaliana. The ZnF domains are essential for binding target genes, but the structural basis remains unclear. Here, we determined crystal structures of the ZnF domains and REF6-DNA complex, revealing a unique REF6-family-specific half-cross-braced ZnF (RCZ) domain and two C2H2-type ZnFs. DNA-binding induces a profound conformational change in the hinge region of REF6. Each REF6 recognizes six bases and DNA methylation reduces the binding affinity. Both the acidic region and basic region are important for the self-association of REF6. The REF6 DNA-binding affinity is determined by the sequence-dependent conformations of DNA and also the cooperativity in different target motifs. The conformational plasticity enables REF6 to function as a global transcriptional regulator that directly binds to many diverse genes, revealing the structural basis for the epigenetic modification recognition.
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Affiliation(s)
- Zizi Tian
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, 100193 Beijing, China
| | - Xiaorong Li
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, 100193 Beijing, China
| | - Min Li
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, 100193 Beijing, China
| | - Wei Wu
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, 100193 Beijing, China
| | - Manfeng Zhang
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, 100193 Beijing, China
| | - Chenjun Tang
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, 100193 Beijing, China
| | - Zhihui Li
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, 100193 Beijing, China
| | - Yunlong Liu
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, 100193 Beijing, China
| | - Zhenhang Chen
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, 100193 Beijing, China
| | - Meiting Yang
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, 100193 Beijing, China
| | - Lulu Ma
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, 100193 Beijing, China
| | - Cody Caba
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4 Canada
| | - Yufeng Tong
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON N9B 3P4 Canada
| | - Hon-Ming Lam
- School of Life Sciences and Center for Soybean Research of the State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Shaodong Dai
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 USA
| | - Zhongzhou Chen
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, 100193 Beijing, China
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Hage C, Falvo F, Schäfer M, Sinz A. Novel Concepts of MS-Cleavable Cross-linkers for Improved Peptide Structure Analysis. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:2022-2038. [PMID: 28653243 DOI: 10.1007/s13361-017-1712-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 05/03/2017] [Accepted: 05/07/2017] [Indexed: 06/07/2023]
Abstract
The chemical cross-linking/mass spectrometry (MS) approach is gaining increasing importance as an alternative method for studying protein conformation and for deciphering protein interaction networks. This study is part of our ongoing efforts to develop innovative cross-linking principles for a facile and efficient assignment of cross-linked products. We evaluate two homobifunctional, amine-reactive, and MS-cleavable cross-linkers regarding their potential for automated analysis of cross-linked products. We introduce the bromine phenylurea (BrPU) linker that possesses a unique structure yielding a distinctive fragmentation pattern on collisional activation. Moreover, BrPU delivers the characteristic bromine isotope pattern and mass defect for all cross-linker-decorated fragments. We compare the fragmentation behavior of the BrPU linker with that of our previously described MS-cleavable TEMPO-Bz linker (which consists of a 2,2,6,6-tetramethylpiperidine-1-oxy moiety connected to a benzyl group) that was developed to perform free-radical-initiated peptide sequencing. Comparative collisional activation experiments (collision-induced dissociation and higher-energy collision-induced dissociation) with both cross-linkers were conducted in negative electrospray ionization mode with an Orbitrap Fusion mass spectrometer using five model peptides. As hypothesized in a previous study, the presence of a cross-linked N-terminal aspartic acid residue seems to be the prerequisite for the loss of an intact peptide from the cross-linked products. As the BrPU linker combines a characteristic mass shift with an isotope signature, it presents a more favorable combination for automated assignment of cross-linked products compared with the TEMPO-Bz linker. ᅟ.
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Affiliation(s)
- Christoph Hage
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Wolfgang-Langenbeck-Str. 4, 06120, Halle (Saale), Germany
| | - Francesco Falvo
- Department of Chemistry, University of Cologne, Greinstr. 4, 50939, Cologne, Germany
- Eurofins Umwelt West GmbH, Vorgebirgsstr. 20, 50389, Wesseling, Germany
| | - Mathias Schäfer
- Department of Chemistry, University of Cologne, Greinstr. 4, 50939, Cologne, Germany
| | - Andrea Sinz
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Wolfgang-Langenbeck-Str. 4, 06120, Halle (Saale), Germany.
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Iacobucci C, Hage C, Schäfer M, Sinz A. A Novel MS-Cleavable Azo Cross-Linker for Peptide Structure Analysis by Free Radical Initiated Peptide Sequencing (FRIPS). JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:2039-2053. [PMID: 28717933 DOI: 10.1007/s13361-017-1744-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 06/13/2017] [Accepted: 06/15/2017] [Indexed: 06/07/2023]
Abstract
The chemical cross-linking/mass spectrometry (MS) approach is a growing research field in structural proteomics that allows gaining insights into protein conformations. It relies on creating distance constraints between cross-linked amino acid side chains that can further be used to derive protein structures. Currently, the most urgent task for designing novel cross-linking principles is an unambiguous and automated assignment of the created cross-linked products. Here, we introduce the homobifunctional, amine-reactive, and water soluble cross-linker azobisimidoester (ABI) as a prototype of a novel class of cross-linkers. The ABI-linker possesses an innovative modular scaffold combining the benefits of collisional activation lability with open shell chemistry. This MS-cleavable cross-linker can be efficiently operated via free radical initiated peptide sequencing (FRIPS) in positive ionization mode. Our proof-of-principle study challenges the gas phase behavior of the ABI-linker for the three amino acids, lysine, leucine, and isoleucine, as well as the model peptide thymopentin. The isomeric amino acids leucine and isoleucine could be discriminated by their characteristic side chain fragments. Collisional activation experiments were conducted via positive electrospray ionization (ESI) on two Orbitrap mass spectrometers. The ABI-mediated formation of odd electron product ions in MS/MS and MS3 experiments was evaluated and compared with a previously described azo-based cross-linker. All cross-linked products were amenable to automated analysis by the MeroX software, underlining the future potential of the ABI-linker for structural proteomics studies. Graphical Abstract ᅟ.
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Affiliation(s)
- Claudio Iacobucci
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Wolfgang-Langenbeck-Str. 4, D-06120, Halle (Saale), Germany.
| | - Christoph Hage
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Wolfgang-Langenbeck-Str. 4, D-06120, Halle (Saale), Germany
| | - Mathias Schäfer
- Department of Chemistry, Institute of Organic Chemistry, University of Cologne, Greinstr. 4, D-50939, Kӧln, Germany
| | - Andrea Sinz
- Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Wolfgang-Langenbeck-Str. 4, D-06120, Halle (Saale), Germany.
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Parker CE, Borchers CH. Editorial. Methods 2015; 89:1-3. [PMID: 26552894 DOI: 10.1016/j.ymeth.2015.10.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Carol E Parker
- University of Victoria-Genome British Columbia Proteomics Centre, Vancouver Island Technology Park, #3101-4464 Markham St., Victoria, BC V8Z 7X8, Canada
| | - Christoph H Borchers
- University of Victoria-Genome British Columbia Proteomics Centre, Vancouver Island Technology Park, #3101-4464 Markham St., Victoria, BC V8Z 7X8, Canada
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