1
|
Cross-linking mass spectrometry for mapping protein complex topologies in situ. Essays Biochem 2023; 67:215-228. [PMID: 36734207 PMCID: PMC10070479 DOI: 10.1042/ebc20220168] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 01/03/2023] [Accepted: 01/05/2023] [Indexed: 02/04/2023]
Abstract
Cross-linking mass spectrometry has become an established technology to provide structural information on the topology and dynamics of protein complexes. Readily accessible workflows can provide detailed data on simplified systems, such as purified complexes. However, using this technology to study the structure of protein complexes in situ, such as in organelles, cells, and even tissues, is still a technological frontier. The complexity of these systems remains a considerable challenge, but there have been dramatic improvements in sample handling, data acquisition, and data processing. Here, we summarise these developments and describe the paths towards comprehensive and comparative structural interactomes by cross-linking mass spectrometry.
Collapse
|
2
|
Sarnowski CP, Bikaki M, Leitner A. Cross-linking and mass spectrometry as a tool for studying the structural biology of ribonucleoproteins. Structure 2022; 30:441-461. [PMID: 35366400 DOI: 10.1016/j.str.2022.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 02/03/2022] [Accepted: 03/01/2022] [Indexed: 11/17/2022]
Abstract
Cross-linking and mass spectrometry (XL-MS) workflows represent an increasingly popular technique for low-resolution structural studies of macromolecular complexes. Cross-linking reactions take place in the solution state, capturing contact sites between components of a complex that represent the native, functionally relevant structure. Protein-protein XL-MS protocols are widely adopted, providing precise localization of cross-linking sites to single amino acid positions within a pair of cross-linked peptides. In contrast, protein-RNA XL-MS workflows are evolving rapidly and differ in their ability to localize interaction regions within the RNA sequence. Here, we review protein-protein and protein-RNA XL-MS workflows, and discuss their applications in studies of protein-RNA complexes. The examples highlight the complementary value of XL-MS in structural studies of protein-RNA complexes, where more established high-resolution techniques might be unable to produce conclusive data.
Collapse
Affiliation(s)
- Chris P Sarnowski
- Institute of Molecular Systems Biology, Department of Biology, ETH Zürich, 8093 Zurich, Switzerland; Systems Biology PhD Program, University of Zürich and ETH Zürich, Zurich, Switzerland
| | - Maria Bikaki
- Institute of Molecular Systems Biology, Department of Biology, ETH Zürich, 8093 Zurich, Switzerland
| | - Alexander Leitner
- Institute of Molecular Systems Biology, Department of Biology, ETH Zürich, 8093 Zurich, Switzerland.
| |
Collapse
|
3
|
Trahan C, Oeffinger M. Targeted Cross-Linking Mass Spectrometry on Single-Step Affinity Purified Molecular Complexes in the Yeast Saccharomyces cerevisiae. Methods Mol Biol 2022; 2456:185-210. [PMID: 35612743 DOI: 10.1007/978-1-0716-2124-0_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Protein cross-linking mass spectrometry (XL-MS) has been developed into a powerful and robust tool that is now well implemented and routinely used by an increasing number of laboratories. While bulk cross-linking of complexes provides useful information on whole complexes, it is limiting for the probing of specific protein "neighbourhoods," or vicinity interactomes. For example, it is not unusual to find cross-linked peptide pairs that are disproportionately overrepresented compared to the surface areas of complexes, while very few or no cross-links are identified in other regions. When studying dynamic complexes along their pathways, some vicinity cross-links may be of too low abundance in the pool of heterogenous complexes of interest to be efficiently identified by standard XL-MS. In this chapter, we describe a targeted XL-MS approach from single-step affinity purified (ssAP) complexes that enables the investigation of specific protein "neighbourhoods" within molecular complexes in yeast, using a small cross-linker anchoring tag, the CH-tag. One advantage of this method over a general cross-linking strategy is the possibility to significantly enrich for localized anchored-cross-links within complexes, thus yielding a higher sensitivity to detect highly dynamic or low abundance protein interactions within a specific protein "neighbourhood" occurring along the pathway of a selected bait protein. Moreover, many variations of the method can be employed; the ssAP-tag and the CH-tag can either be fused to the same or different proteins in the complex, or the CH-tag can be fused to multiple protein components in the same cell line to explore dynamic vicinity interactions along a pathway.
Collapse
Affiliation(s)
- Christian Trahan
- Institut de recherches cliniques de Montréal, Montréal, QC, Canada
| | - Marlene Oeffinger
- Institut de recherches cliniques de Montréal, Montréal, QC, Canada.
- Département de biochimie, Faculté de médecine, Université de Montréal, Montréal, QC, Canada.
- Faculty of Medicine, Division of Experimental Medicine, McGill University, Montréal, QC, Canada.
| |
Collapse
|
4
|
Yugandhar K, Zhao Q, Gupta S, Xiong D, Yu H. Progress in methodologies and quality-control strategies in protein cross-linking mass spectrometry. Proteomics 2021; 21:e2100145. [PMID: 34647422 DOI: 10.1002/pmic.202100145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 10/04/2021] [Indexed: 11/10/2022]
Abstract
Deciphering the interaction networks and structural dynamics of proteins is pivotal to better understanding their biological functions. Cross-linking mass spectrometry (XL-MS) is a powerful and increasingly popular technology that provides information about protein-protein interactions and their structural constraints for individual proteins and multiprotein complexes on a proteome-scale. In this review, we first assess the coverage and depth of the XL-MS technique by utilizing publicly available datasets. We then delve into the progress in XL-MS experimental and computational methodologies and examine different quality-control strategies reported in the literature. Finally, we discuss the progress in XL-MS applications along with the scope for future improvements.
Collapse
Affiliation(s)
- Kumar Yugandhar
- Department of Computational Biology, Cornell University, New York, USA.,Weill Institute for Cell and Molecular Biology, Cornell University, New York, USA
| | - Qiuye Zhao
- Department of Computational Biology, Cornell University, New York, USA.,Weill Institute for Cell and Molecular Biology, Cornell University, New York, USA
| | - Shobhita Gupta
- Department of Computational Biology, Cornell University, New York, USA.,Weill Institute for Cell and Molecular Biology, Cornell University, New York, USA
| | - Dapeng Xiong
- Department of Computational Biology, Cornell University, New York, USA.,Weill Institute for Cell and Molecular Biology, Cornell University, New York, USA
| | - Haiyuan Yu
- Department of Computational Biology, Cornell University, New York, USA.,Weill Institute for Cell and Molecular Biology, Cornell University, New York, USA
| |
Collapse
|
5
|
Matzinger M, Kandioller W, Doppler P, Heiss EH, Mechtler K. Fast and Highly Efficient Affinity Enrichment of Azide-A-DSBSO Cross-Linked Peptides. J Proteome Res 2020; 19:2071-2079. [PMID: 32250121 PMCID: PMC7199212 DOI: 10.1021/acs.jproteome.0c00003] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
![]()
Cross-linking mass spectrometry is
an increasingly used, powerful
technique to study protein–protein interactions or to provide
structural information. Due to substochiometric reaction efficiencies,
cross-linked peptides are usually low abundance. This results in challenging
data evaluation and the need for an effective enrichment. Here we
describe an improved, easy to implement, one-step method to enrich
azide-tagged, acid-cleavable disuccinimidyl bis-sulfoxide (DSBSO)
cross-linked peptides using dibenzocyclooctyne (DBCO) coupled Sepharose
beads. We probed this method using recombinant Cas9 and E. coli ribosome. For Cas9, the number of detectable cross-links was increased
from ∼100 before enrichment to 580 cross-links after enrichment.
To mimic a cellular lysate, E. coli ribosome
was spiked into a tryptic HEK background at a ratio of 1:2–1:100.
The number of detectable unique cross-links was maintained high at
∼100. The estimated enrichment efficiency was improved by a
factor of 4–5 (based on XL numbers) compared to enrichment
via biotin and streptavidin. We were still able to detect cross-links
from 0.25 μg cross-linked E. coli ribosomes
in a background of 100 μg tryptic HEK peptides, indicating a
high enrichment sensitivity. In contrast to conventional enrichment
techniques, like SEC, the time needed for preparation and MS measurement
is significantly reduced. This robust, fast, and selective enrichment
method for azide-tagged linkers will contribute to mapping protein–protein
interactions, investigating protein architectures in more depth, and
helping to understand complex biological processes.
Collapse
Affiliation(s)
- Manuel Matzinger
- Department of Pharmacognosy, Faculty of Life Sciences, University of Vienna, 1090 Vienna, Austria.,Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030 Vienna, Austria
| | - Wolfgang Kandioller
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, 1090 Vienna, Austria
| | - Philipp Doppler
- Institute of Chemical, Environmental and Bioscience Engineering, Vienna University of Technology, 1040 Vienna, Austria
| | - Elke H Heiss
- Department of Pharmacognosy, Faculty of Life Sciences, University of Vienna, 1090 Vienna, Austria
| | - Karl Mechtler
- Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), 1030 Vienna, Austria.,Institute of Molecular Biotechnology, Austrian Academy of Sciences, Vienna BioCenter (VBC), 1030 Vienna, Austria
| |
Collapse
|
6
|
Zhao B, Reilly CP, Reilly JP. ETD-Cleavable Linker for Confident Cross-linked Peptide Identifications. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:1631-1642. [PMID: 31098958 DOI: 10.1007/s13361-019-02227-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 04/12/2019] [Accepted: 04/13/2019] [Indexed: 06/09/2023]
Abstract
Peptide cross-links formed using the homobifunctional-linker diethyl suberthioimidate (DEST) are shown to be ETD-cleavable. DEST has a spacer arm consisting of a 6-carbon alkyl chain and it cleaves at the amidino groups created upon reaction with primary amines. In ETD MS2 spectra, DEST cross-links can be recognized based on mass pairs consisting of peptide-NH2• and peptide+linker+NH3 ions, and backbone cleavages are more equally distributed over the two constituent peptides compared with collisional activation. Dead ends that are often challenging to distinguish from cross-links are diagnosed by intense reporter ions. ETD mass pairs can be used in MS3 experiments to confirm cross-link identifications. These features provide a simple but reliable approach to identify cross-links that should facilitate studies of protein complexes.
Collapse
Affiliation(s)
- Bingqing Zhao
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, IN, 47405, USA
| | - Colin P Reilly
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, IN, 47405, USA
| | - James P Reilly
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, IN, 47405, USA.
| |
Collapse
|
7
|
Luo J, Bassett J, Ranish J. Identification of Cross-linked Peptides Using Isotopomeric Cross-linkers. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:1643-1653. [PMID: 31168746 PMCID: PMC7069596 DOI: 10.1007/s13361-019-02253-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 05/08/2019] [Accepted: 05/20/2019] [Indexed: 06/09/2023]
Abstract
Chemical cross-linking combined with mass spectrometry (CL-MS) is a powerful method for characterizing the architecture of protein assemblies and for mapping protein-protein interactions. Despite its proven utility, confident identification of cross-linked peptides remains a formidable challenge, especially when the peptides are derived from complex mixtures. MS cleavable cross-linkers are gaining importance for CL-MS as they permit reliable identification of cross-linked peptides by whole proteome database searching using MS/MS information. Here we introduce a novel class of MS cleavable cross-linkers called isotopomeric cross-linkers (ICLs), which allow for confident and efficient identification of cross-linked peptides by whole proteome database searching. ICLs are simple, symmetrical molecules that asymmetrically incorporate heavy and light stable isotopes into the two arms of the cross-linker. As a result of this property, ICLs automatically generate pairs of isotopomeric cross-linked peptides, which differ only by the positions of the heavy and light isotopes. Upon fragmentation during MS analysis, these isotopomeric cross-linked peptides generate unique isotopic doublet ions that correspond to the individual peptides in the cross-link. The doublet ion information is used to determine the masses of the two cross-linked peptides from the same MS2 spectrum that is also used for peptide spectrum matching (PSM) by sequence database searching. Here we present the rationale for and mechanism of cross-linked peptide identification by ICL-MS. We describe the synthesis of the ICL-1 reagent, the ICL-MS workflow, and the performance characteristics of ICL-MS for identifying cross-linked peptides derived from increasingly complex mixtures by whole proteome database searching.
Collapse
Affiliation(s)
- Jie Luo
- Institute for Systems Biology, 401 Terry Ave North, Seattle, WA, 98109, USA
| | - Jacob Bassett
- Institute for Systems Biology, 401 Terry Ave North, Seattle, WA, 98109, USA
| | - Jeff Ranish
- Institute for Systems Biology, 401 Terry Ave North, Seattle, WA, 98109, USA.
| |
Collapse
|
8
|
Gutierrez CB, Block SA, Yu C, Soohoo SM, Huszagh AS, Rychnovsky SD, Huang L. Development of a Novel Sulfoxide-Containing MS-Cleavable Homobifunctional Cysteine-Reactive Cross-Linker for Studying Protein-Protein Interactions. Anal Chem 2018; 90:7600-7607. [PMID: 29792801 PMCID: PMC6037416 DOI: 10.1021/acs.analchem.8b01287] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cross-linking mass spectrometry (XL-MS) has become an emerging technology for defining protein-protein interactions (PPIs) and elucidating architectures of large protein complexes. Up to now, the most widely used cross-linking reagents target lysines. Although such reagents have been successfully applied to map PPIs at the proteome-wide scale, comprehensive PPI profiling would require additional cross-linking chemistries. Cysteine is one of the most reactive amino acids and an attractive target for cross-linking owing to its unique role in protein structures. Although sulfhydryl-reactive cross-linkers are commercially available, their applications in XL-MS studies remain sparse, likely due to the difficulty in identifying cysteine cross-linked peptides. Previously, we developed a new class of sulfoxide-containing MS-cleavable cross-linkers to enable fast and accurate identification of cross-linked peptides using multistage tandem mass spectrometry (MS n). Here, we present the development of a new sulfoxide-containing MS-cleavable homobifunctional cysteine-reactive cross-linker, bismaleimide sulfoxide (BMSO). We demonstrate that BMSO-cross-linked peptides display the same characteristic fragmentation pattern during collision-induced dissociation (CID) as other sulfoxide-containing MS-cleavable cross-linked peptides, thus permitting their simplified analysis and unambiguous identification by MS n. Additionally, we show that BMSO can complement amine- and acidic-residue-reactive reagents for mapping protein-interaction regions. Collectively, this work not only enlarges the toolbox of MS-cleavable cross-linkers with diverse chemistries, but more importantly expands our capacity and capability of studying PPIs in general.
Collapse
Affiliation(s)
- Craig B. Gutierrez
- Department of Physiology and Biophysics, University of California, Irvine, CA 92697
| | - Sarah A. Block
- Department of Chemistry, University of California, Irvine, CA 92697
| | - Clinton Yu
- Department of Physiology and Biophysics, University of California, Irvine, CA 92697
| | - Stephanie M. Soohoo
- Department of Physiology and Biophysics, University of California, Irvine, CA 92697
| | - Alexander S. Huszagh
- Department of Physiology and Biophysics, University of California, Irvine, CA 92697
| | | | - Lan Huang
- Department of Physiology and Biophysics, University of California, Irvine, CA 92697
| |
Collapse
|
9
|
Yu C, Huang L. Cross-Linking Mass Spectrometry: An Emerging Technology for Interactomics and Structural Biology. Anal Chem 2018; 90:144-165. [PMID: 29160693 PMCID: PMC6022837 DOI: 10.1021/acs.analchem.7b04431] [Citation(s) in RCA: 222] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Clinton Yu
- Department of Physiology & Biophysics, University of California, Irvine, Irvine, CA 92697
| | - Lan Huang
- Department of Physiology & Biophysics, University of California, Irvine, Irvine, CA 92697
| |
Collapse
|
10
|
Abstract
![]()
Cross-linking/mass
spectrometry is an increasingly popular approach
to obtain structural information on proteins and their complexes in
solution. However, methods for error assessment are under current
development. We note that false-discovery rates can be estimated at
different points during data analysis, and are most relevant for residue
or protein pairs. Missing this point led in our example analysis to
an actual 8.4% error when 5% error was targeted. In addition, prefiltering
of peptide-spectrum matches and of identified peptide pairs substantially
improved results. In our example, this prefiltering increased the
number of residue pairs (5% FDR) by 33% (n = 108
to n = 144). This number improvement did not come
at the expense of reduced accuracy as the added data agreed with an
available crystal structure. We provide an open-source tool, xiFDR
(https://github.com/rappsilberlab/xiFDR), that implements our observations for routine application. Data
are available via ProteomeXchange with identifier PXD004749.
Collapse
Affiliation(s)
- Lutz Fischer
- Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh , Edinburgh EH9 3BF, United Kingdom
| | - Juri Rappsilber
- Wellcome Trust Centre for Cell Biology, School of Biological Sciences, University of Edinburgh , Edinburgh EH9 3BF, United Kingdom.,Chair of Bioanalytics, Institute of Biotechnology, Technische Universität Berlin , 13355 Berlin, Germany
| |
Collapse
|
11
|
Pollard RD, Fulp B, Sorci-Thomas MG, Thomas MJ. High-Density Lipoprotein Biogenesis: Defining the Domains Involved in Human Apolipoprotein A-I Lipidation. Biochemistry 2016; 55:4971-81. [PMID: 27501467 DOI: 10.1021/acs.biochem.6b00347] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The first step in removing cholesterol from a cell is the ATP-binding cassette transporter 1 (ABCA1)-driven transfer of cholesterol to lipid-free or lipid-poor apolipoprotein A-I (apoA-I), which yields cholesterol-rich nascent high-density lipoprotein (nHDL) that then matures in plasma to spherical, cholesteryl ester-rich HDL. However, lipid-free apoA-I has a three-dimensional (3D) conformation that is significantly different from that of lipidated apoA-I on nHDL. By comparing the lipid-free apoA-I 3D conformation of apoA-I to that of 9-14 nm diameter nHDL, we formulated the hypothetical helical domain transitions that might drive particle formation. To test the hypothesis, ten apoA-I mutants were prepared that contained two strategically placed cysteines several of which could form intramolecular disulfide bonds and others that could not form these bonds. Mass spectrometry was used to identify amino acid sequence and intramolecular disulfide bond formation. Recombinant HDL (rHDL) formation was assessed with this group of apoA-I mutants. ABCA1-driven nHDL formation was measured in four mutants and wild-type apoA-I. The mutants contained cysteine substitutions in one of three regions: the N-terminus, amino acids 34 and 55 (E34C to S55C), central domain amino acids 104 and 162 (F104C to H162C), and the C-terminus, amino acids 200 and 233 (L200C to L233C). Mutants were studied in the locked form, with an intramolecular disulfide bond present, or unlocked form, with the cysteine thiol blocked by alkylation. Only small amounts of rHDL or nHDL were formed upon locking the central domain. We conclude that both the N- and C-terminal ends assist in the initial steps in lipid acquisition, but that opening of the central domain was essential for particle formation.
Collapse
Affiliation(s)
- Ricquita D Pollard
- Section on Molecular Medicine, Department of Internal Medicine, Wake Forest School of Medicine , Winston-Salem, North Carolina 27101, United States
| | - Brian Fulp
- Department of Biochemistry, Wake Forest School of Medicine , Winston-Salem, North Carolina 27101, United States
| | - Mary G Sorci-Thomas
- Departments of Medicine, Division of Endocrinology, Pharmacology and Toxicology, and Blood Research Institute, BloodCenter of Wisconsin, Medical College of Wisconsin , Milwaukee, Wisconsin 53226, United States
| | - Michael J Thomas
- Department of Pharmacology and Toxicology, Medical College of Wisconsin , 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226, United States
| |
Collapse
|
12
|
Kandur WV, Kao A, Vellucci D, Huang L, Rychnovsky SD. Design of CID-cleavable protein cross-linkers: identical mass modifications for simpler sequence analysis. Org Biomol Chem 2016; 13:9793-807. [PMID: 26269432 DOI: 10.1039/c5ob01410g] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The cross-linking Mass Spectrometry (XL-MS) technique has enormous potential for studying the interactions between proteins, and it can provide detailed structural information about the interaction interfaces in large protein complexes. Such information has been difficult to obtain by conventional structural methods. One of the primary impediments to the wider use of the XL-MS technique is the extreme challenge in sequencing cross-linked peptides because of their complex fragmentation patterns in MS. A recent innovation is the development of MS-cleavable cross-linkers, which allows direct sequencing of component peptides for facile identification. Sulfoxides are an intriguing class of thermally-cleavable compounds that have been shown to fragment selectively during low-energy collisional induced dissociation (CID) analysis. Current CID-cleavable cross-linkers create fragmentation patterns in MS(2) of multiple peaks for each cross-linked peptide. Reducing the complexity of the fragmentation pattern in MS(2) facilitates subsequent MS(3) sequencing of the cross-linked peptides. The first authentic identical mass linker (IML) has now been designed, prepared, and evaluated. Multistage tandem mass spectrometry (MS(n)) analysis has demonstrated that the IML cross-linked peptides indeed yield one peak per peptide constituent in MS(2) as predicted, thus allowing effective and sensitive MS(3) analysis for unambiguous identification. Selective fragmentation for IML cross-linked peptides from the 19S proteasome complex was observed, providing a proof-of-concept demonstration for XL-MS studies on protein complexes.
Collapse
Affiliation(s)
- Wynne V Kandur
- Department of Chemistry, University of California, Irvine, CA 92697, USA.
| | | | | | | | | |
Collapse
|
13
|
Protein-protein interaction analysis for functional characterization of helicases. Methods 2016; 108:56-64. [PMID: 27090004 DOI: 10.1016/j.ymeth.2016.04.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 04/11/2016] [Accepted: 04/13/2016] [Indexed: 11/22/2022] Open
Abstract
Helicases are enzymes involved in nucleic acid metabolism, playing major roles in replication, transcription, and repair. Defining helicases oligomerization state and transient and persistent protein interactions is essential for understanding of their function. In this article we review current methods for the protein-protein interaction analysis, and discuss examples of its application to the study of helicases: Pif1 and DDX3. Proteomics methods are our main focus - affinity pull-downs and chemical cross-linking followed by mass spectrometry. We review advantages and limitations of these methods and provide general guidelines for their implementation in the functional analysis of helicases.
Collapse
|
14
|
Tan D, Li Q, Zhang MJ, Liu C, Ma C, Zhang P, Ding YH, Fan SB, Tao L, Yang B, Li X, Ma S, Liu J, Feng B, Liu X, Wang HW, He SM, Gao N, Ye K, Dong MQ, Lei X. Trifunctional cross-linker for mapping protein-protein interaction networks and comparing protein conformational states. eLife 2016; 5. [PMID: 26952210 PMCID: PMC4811778 DOI: 10.7554/elife.12509] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 02/26/2016] [Indexed: 12/20/2022] Open
Abstract
To improve chemical cross-linking of proteins coupled with mass spectrometry (CXMS), we developed a lysine-targeted enrichable cross-linker containing a biotin tag for affinity purification, a chemical cleavage site to separate cross-linked peptides away from biotin after enrichment, and a spacer arm that can be labeled with stable isotopes for quantitation. By locating the flexible proteins on the surface of 70S ribosome, we show that this trifunctional cross-linker is effective at attaining structural information not easily attainable by crystallography and electron microscopy. From a crude Rrp46 immunoprecipitate, it helped identify two direct binding partners of Rrp46 and 15 protein-protein interactions (PPIs) among the co-immunoprecipitated exosome subunits. Applying it to E. coli and C. elegans lysates, we identified 3130 and 893 inter-linked lysine pairs, representing 677 and 121 PPIs. Using a quantitative CXMS workflow we demonstrate that it can reveal changes in the reactivity of lysine residues due to protein-nucleic acid interaction. DOI:http://dx.doi.org/10.7554/eLife.12509.001 Proteins fold into structures that are determined by the order of the amino acids that they are built from. These structures enable the protein to carry out its role, which often involves interacting with other proteins. Chemical cross-linking coupled with mass spectrometry (CXMS) is a powerful method used to study protein structure and how proteins interact, with a benefit of stabilizing and capturing brief interactions. CXMS uses a chemical compound called a linker that has two arms, each of which can bind specific amino acids in a protein or in multiple proteins. Only when the regions are close to each other can they be “cross-linked” in this way. After cross-linking, the proteins are cut into small pieces known as peptides. The cross-linked peptides are then separated from the non cross-linked ones and characterized. Although CXMS is a popular method, there are aspects about it that limit its use. It does not work well on complex samples that contain lots of different proteins, as it is difficult to separate the cross-linked peptides from the overwhelming amounts of non cross-linked peptides. Also, although it can be used to detect changes in the shape of a protein, which are often crucial to the protein's role, the method has not been smoothed out. Tan, Li et al. have now developed a new cross-linker called Leiker that addresses these limitations. Leiker cross-links the amino acid lysine to another lysine, and contains a molecular tag that allows cross-linked peptides to be efficiently purified away from non cross-linked peptides. As part of a streamlined workflow to detect changes in the shape of a protein, Leiker also contains a region that can be labeled. Analysing a bacterial ribosome, which contains more than 50 proteins, showed that Leiker-based CXMS could detect many more protein interactions than previous studies had. These included interactions that changed too rapidly to be studied by other structural methods. Tan, Li et al. then applied Leiker-based CXMS to the entire contents of bacterial cells at different stages of growth, and identified a protein interaction that is only found in growing cells. In future, Leiker will be useful for analyzing the structure of large protein complexes, probing changes in protein structure, and mapping the interactions between proteins in complex mixtures. DOI:http://dx.doi.org/10.7554/eLife.12509.002
Collapse
Affiliation(s)
- Dan Tan
- Graduate Program, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China.,National Institute of Biological Sciences, Beijing, China
| | - Qiang Li
- National Institute of Biological Sciences, Beijing, China.,Synthetic and Functional Biomolecules Center, Peking University, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China.,Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Mei-Jun Zhang
- National Institute of Biological Sciences, Beijing, China
| | - Chao Liu
- Key Lab of Intelligent Information Processing of Chinese Academy of Sciences, Institute of Computing Technology, Chinese Academy of Sciences, Beijing, China
| | - Chengying Ma
- Ministry of Education Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Pan Zhang
- Graduate Program, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China.,National Institute of Biological Sciences, Beijing, China
| | - Yue-He Ding
- Graduate Program, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China.,National Institute of Biological Sciences, Beijing, China
| | - Sheng-Bo Fan
- Key Lab of Intelligent Information Processing of Chinese Academy of Sciences, Institute of Computing Technology, Chinese Academy of Sciences, Beijing, China
| | - Li Tao
- Graduate Program, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China.,National Institute of Biological Sciences, Beijing, China
| | - Bing Yang
- National Institute of Biological Sciences, Beijing, China
| | - Xiangke Li
- National Institute of Biological Sciences, Beijing, China
| | - Shoucai Ma
- National Institute of Biological Sciences, Beijing, China
| | - Junjie Liu
- Ministry of Education Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Boya Feng
- Ministry of Education Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Xiaohui Liu
- National Institute of Biological Sciences, Beijing, China
| | - Hong-Wei Wang
- Ministry of Education Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Si-Min He
- Key Lab of Intelligent Information Processing of Chinese Academy of Sciences, Institute of Computing Technology, Chinese Academy of Sciences, Beijing, China
| | - Ning Gao
- Ministry of Education Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Keqiong Ye
- National Institute of Biological Sciences, Beijing, China
| | - Meng-Qiu Dong
- Graduate Program, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China.,National Institute of Biological Sciences, Beijing, China
| | - Xiaoguang Lei
- National Institute of Biological Sciences, Beijing, China.,Synthetic and Functional Biomolecules Center, Peking University, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China.,Department of Chemical Biology, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| |
Collapse
|
15
|
Abstract
Specific conformations of signaling proteins can serve as “signals” in signal transduction by being recognized by receptors.
Collapse
Affiliation(s)
- Peter Tompa
- VIB Structural Biology Research Center (SBRC)
- Brussels
- Belgium
- Vrije Universiteit Brussel
- Brussels
| |
Collapse
|
16
|
Leitner A, Faini M, Stengel F, Aebersold R. Crosslinking and Mass Spectrometry: An Integrated Technology to Understand the Structure and Function of Molecular Machines. Trends Biochem Sci 2016; 41:20-32. [DOI: 10.1016/j.tibs.2015.10.008] [Citation(s) in RCA: 226] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 10/18/2015] [Accepted: 10/29/2015] [Indexed: 01/30/2023]
|
17
|
Burke AM, Kandur W, Novitsky EJ, Kaake RM, Yu C, Kao A, Vellucci D, Huang L, Rychnovsky SD. Synthesis of two new enrichable and MS-cleavable cross-linkers to define protein-protein interactions by mass spectrometry. Org Biomol Chem 2015; 13:5030-7. [PMID: 25823605 DOI: 10.1039/c5ob00488h] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The cross-linking Mass Spectrometry (XL-MS) technique extracts structural information from protein complexes without requiring highly purified samples, crystallinity, or large amounts of material. However, there are challenges to applying the technique to protein complexes in vitro, and those challenges become more daunting with in vivo experiments. Issues include effective detection and identification of cross-linked peptides from complex mixtures. While MS-cleavable cross-linkers facilitate the sequencing and identification of cross-linked peptides, enrichable cross-linkers increase their detectability by allowing their separation from non-cross-linked peptides prior to MS analysis. Although a number of cross-linkers with single functionality have been developed in recent years, an ideal reagent would incorporate both capabilities for XL-MS studies. Therefore, two new cross-linkers have been designed and prepared that incorporate an azide (azide-A-DSBSO) or alkyne (alkyne-A-DSBSO) to enable affinity purification strategies based on click chemistry. The integration of an acid cleavage site next to the enrichment handle allows easy recovery of cross-linked products during affinity purification. In addition, these sulfoxide containing cross-linking reagents possess robust MS-cleavable bonds to facilitate fast and easy identification of cross-linked peptides using MS analysis. Optimized, gram-scale syntheses of these cross-linkers have been developed and the azide-A-DSBSO cross-linker has been evaluated with peptides and proteins to demonstrate its utility in XL-MS analysis.
Collapse
Affiliation(s)
- Anthony M Burke
- Department of Chemistry, University of California, Irvine, CA 92697, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Zybailov B, Gokulan K, Wiese J, Ramanagoudr-Bhojappa R, Byrd AK, Glazko G, Jaiswal M, Mackintosh S, Varughese KI, Raney KD. Analysis of Protein-protein Interaction Interface between Yeast Mitochondrial Proteins Rim1 and Pif1 Using Chemical Cross-linking Mass Spectrometry. ACTA ACUST UNITED AC 2015; 8:243-252. [PMID: 26807012 DOI: 10.4172/jpb.1000376] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Defining protein-protein contacts is a challenging problem and cross-linking is a promising solution. Here, we present a case of mitochondrial single strand binding protein Rim1 and helicase Pif1, an interaction first observed in immuno-affinity pull-down from yeast cells using Pif1 bait. We found that only the short succinimidyl-diazirine cross-linker or formaldehyde captured the interaction between recombinant Rim1 and Pif1. In addition, Pif1 needed to be stripped of its N-terminal and C-terminal domains, and Rim1's C-terminus needed to be modified for the cross-linked product to become visible. Our report is an example of a non-trivial analysis, where a previously identified stable interaction escapes initial capture with cross-linking agents and requires substantial modification to recombinant proteins and fine-tuning of the mass spectrometry-based methods for the cross-links to become detectable. We used high resolution mass spectrometry to detect the cross-linked peptides. A 1:1 mixture of 15N and 14N-labeled Rim1 was used to validate the cross-links by their mass shift in the LC-MS profiles. Two sites on Rim1 were confirmed: 1) the N-terminus, and 2) the K29 residue. Performing cross-linking with a K29A variant visibly reduced the cross-linked product. Further, K29A-Rim1 showed a five-fold lower affinity to single stranded DNA compared to wild-type Rim1. Both the K29A variant and wild type Rim1 showed similar degrees of stimulation of Pif1 helicase activity. We propose structural models of the Pif1-Rim1 interaction and discuss its functional significance. Our work represents a non-trivial protein-protein interface analysis and demonstrates utility of short and non-specific cross-linkers.
Collapse
Affiliation(s)
- Boris Zybailov
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Kuppan Gokulan
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR-72205, USA
| | - Jadon Wiese
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | | | - Alicia K Byrd
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Galina Glazko
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, USA
| | - Mihir Jaiswal
- UALR/UAMS joint bioinformatics program, University of Arkansas Little Rock, Little Rock, AR, USA
| | - Samuel Mackintosh
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Kottayil I Varughese
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR-72205, USA
| | - Kevin D Raney
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| |
Collapse
|
19
|
Fan SB, Meng JM, Lu S, Zhang K, Yang H, Chi H, Sun RX, Dong MQ, He SM. Using pLink to Analyze Cross-Linked Peptides. ACTA ACUST UNITED AC 2015; 49:8.21.1-8.21.19. [PMID: 25754995 DOI: 10.1002/0471250953.bi0821s49] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
pLink is a search engine for high-throughput identification of cross-linked peptides from their tandem mass spectra, which is the data-analysis step in chemical cross-linking of proteins coupled with mass spectrometry analysis. pLink has accumulated more than 200 registered users from all over the world since its first release in 2012. After 2 years of continual development, a new version of pLink has been released, which is at least 40 times faster, more versatile, and more user-friendly. Also, the function of the new pLink has been expanded to identifying endogenous protein cross-linking sites such as disulfide bonds and SUMO (Small Ubiquitin-like MOdifier) modification sites. Integrated into the new version are two accessory tools: pLabel, to annotate spectra of cross-linked peptides for visual inspection and publication, and pConfig, to assist users in setting up search parameters. Here, we provide detailed guidance on running a database search for identification of protein cross-links using the 2014 version of pLink.
Collapse
Affiliation(s)
- Sheng-Bo Fan
- Key Lab of Intelligent Information Processing of Chinese Academy of Sciences (CAS), Institute of Computing Technology, CAS, Beijing, China.,University of the Chinese Academy of Sciences, Beijing, China
| | - Jia-Ming Meng
- Key Lab of Intelligent Information Processing of Chinese Academy of Sciences (CAS), Institute of Computing Technology, CAS, Beijing, China.,University of the Chinese Academy of Sciences, Beijing, China
| | - Shan Lu
- National Institute of Biological Sciences, Beijing, China
| | - Kun Zhang
- Key Lab of Intelligent Information Processing of Chinese Academy of Sciences (CAS), Institute of Computing Technology, CAS, Beijing, China.,University of the Chinese Academy of Sciences, Beijing, China
| | - Hao Yang
- Key Lab of Intelligent Information Processing of Chinese Academy of Sciences (CAS), Institute of Computing Technology, CAS, Beijing, China.,University of the Chinese Academy of Sciences, Beijing, China
| | - Hao Chi
- Key Lab of Intelligent Information Processing of Chinese Academy of Sciences (CAS), Institute of Computing Technology, CAS, Beijing, China
| | - Rui-Xiang Sun
- Key Lab of Intelligent Information Processing of Chinese Academy of Sciences (CAS), Institute of Computing Technology, CAS, Beijing, China
| | - Meng-Qiu Dong
- National Institute of Biological Sciences, Beijing, China
| | - Si-Min He
- Key Lab of Intelligent Information Processing of Chinese Academy of Sciences (CAS), Institute of Computing Technology, CAS, Beijing, China
| |
Collapse
|
20
|
Pireyre M, Burow M. Regulation of MYB and bHLH transcription factors: a glance at the protein level. MOLECULAR PLANT 2015; 8:378-88. [PMID: 25667003 DOI: 10.1016/j.molp.2014.11.022] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 11/10/2014] [Accepted: 11/24/2014] [Indexed: 05/07/2023]
Abstract
In complex, constantly changing environments, plants have developed astonishing survival strategies. These elaborated strategies rely on rapid and precise gene regulation mediated by transcription factors (TFs). TFs represent a large fraction of plant genomes and among them, MYBs and basic helix-loop-helix (bHLHs) have unique inherent properties specific to plants. Proteins of these two TF families can act as homo- or heterodimers, associate with proteins from other protein families, or form MYB/bHLH complexes to regulate distinct cellular processes. The ability of MYBs and bHLHs to interact with multiple protein partners has evolved to keep up with the increased metabolic complexity of multi-cellular organisms. Association and disassociation of dynamic TF complexes in response to developmental and environmental cues are controlled through a plethora of regulatory mechanisms specifically modulating TF activity. Regulation of TFs at the protein level is critical for efficient and precise control of their activity, and thus provides the mechanistic basis for a rapid on-and-off switch of TF activity. In this review, examples of post-translational modifications, protein-protein interactions, and subcellular mobilization of TFs are discussed with regard to the relevance of these regulatory mechanisms for the specific activation of MYBs and bHLHs in response to a given environmental stimulus.
Collapse
Affiliation(s)
- Marie Pireyre
- DynaMo DNRF Center of Excellence, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Meike Burow
- DynaMo DNRF Center of Excellence, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark.
| |
Collapse
|
21
|
Kaake RM, Wang X, Burke A, Yu C, Kandur W, Yang Y, Novtisky EJ, Second T, Duan J, Kao A, Guan S, Vellucci D, Rychnovsky SD, Huang L. A new in vivo cross-linking mass spectrometry platform to define protein-protein interactions in living cells. Mol Cell Proteomics 2014; 13:3533-43. [PMID: 25253489 DOI: 10.1074/mcp.m114.042630] [Citation(s) in RCA: 142] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Protein-protein interactions (PPIs) are fundamental to the structure and function of protein complexes. Resolving the physical contacts between proteins as they occur in cells is critical to uncovering the molecular details underlying various cellular activities. To advance the study of PPIs in living cells, we have developed a new in vivo cross-linking mass spectrometry platform that couples a novel membrane-permeable, enrichable, and MS-cleavable cross-linker with multistage tandem mass spectrometry. This strategy permits the effective capture, enrichment, and identification of in vivo cross-linked products from mammalian cells and thus enables the determination of protein interaction interfaces. The utility of the developed method has been demonstrated by profiling PPIs in mammalian cells at the proteome scale and the targeted protein complex level. Our work represents a general approach for studying in vivo PPIs and provides a solid foundation for future studies toward the complete mapping of PPI networks in living systems.
Collapse
Affiliation(s)
- Robyn M Kaake
- From the ‡Department of Physiology & Biophysics, University of California, Irvine, California 92697
| | - Xiaorong Wang
- From the ‡Department of Physiology & Biophysics, University of California, Irvine, California 92697
| | - Anthony Burke
- ¶Department of Chemistry, University of California, Irvine, California 92697
| | - Clinton Yu
- From the ‡Department of Physiology & Biophysics, University of California, Irvine, California 92697
| | - Wynne Kandur
- ¶Department of Chemistry, University of California, Irvine, California 92697
| | - Yingying Yang
- From the ‡Department of Physiology & Biophysics, University of California, Irvine, California 92697
| | - Eric J Novtisky
- ¶Department of Chemistry, University of California, Irvine, California 92697
| | - Tonya Second
- ‖Thermo Fisher Scientific, 355 River Oaks Parkway, San Jose, California 95134
| | - Jicheng Duan
- From the ‡Department of Physiology & Biophysics, University of California, Irvine, California 92697
| | - Athit Kao
- From the ‡Department of Physiology & Biophysics, University of California, Irvine, California 92697
| | - Shenheng Guan
- **Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143
| | - Danielle Vellucci
- ¶Department of Chemistry, University of California, Irvine, California 92697
| | - Scott D Rychnovsky
- ¶Department of Chemistry, University of California, Irvine, California 92697
| | - Lan Huang
- From the ‡Department of Physiology & Biophysics, University of California, Irvine, California 92697;
| |
Collapse
|
22
|
Płociński P, Laubitz D, Cysewski D, Stoduś K, Kowalska K, Dziembowski A. Identification of protein partners in mycobacteria using a single-step affinity purification method. PLoS One 2014; 9:e91380. [PMID: 24664103 PMCID: PMC3963859 DOI: 10.1371/journal.pone.0091380] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 02/07/2014] [Indexed: 12/04/2022] Open
Abstract
Tuberculosis is a leading cause of death in developing countries. Efforts are being made to both prevent its spread and improve curability rates. Understanding the biology of the bacteria causing the disease, Mycobacterium tuberculosis (M. tuberculosis), is thus vital. We have implemented improved screening methods for protein–protein interactions based on affinity purification followed by high-resolution mass spectrometry. This method can be efficiently applied to both medium- and high-throughput studies aiming to characterize protein–protein interaction networks of tubercle bacilli. Of the 4 tested epitopes FLAG, enhanced green fluorescent protein (eGFP), protein A and haemagglutinin, the eGFP tag was found to be most useful on account of its easily monitored expression and its ability to function as a simultaneous tool for subcellular localization studies. It presents a relatively low background with cost-effective purification. RNA polymerase subunit A (RpoA) was used as a model for investigation of a large protein complex. When used as bait, it co-purified with all remaining RNA polymerase core subunits as well as many accessory proteins. The amount of RpoA strongly correlated with the amount of quantification peptide used as part of the tagging system in this study (SH), making it applicable for semi-quantification studies. Interactions between the components of the RpoA-eGFP protein complex were further confirmed using protein cross-linking. Dynamic changes in the composition of protein complexes under induction of UV damage were observed when UvrA-eGFP expressing cells treated with UV light were used to co-purify UvrA interaction partners.
Collapse
Affiliation(s)
- Przemysław Płociński
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warszawa, Poland
| | - Daniel Laubitz
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warszawa, Poland
| | - Dominik Cysewski
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warszawa, Poland
| | - Krystian Stoduś
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warszawa, Poland
| | - Katarzyna Kowalska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warszawa, Poland
| | - Andrzej Dziembowski
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warszawa, Poland
- Department of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
- * E-mail:
| |
Collapse
|
23
|
Trnka MJ, Baker PR, Robinson PJJ, Burlingame AL, Chalkley RJ. Matching cross-linked peptide spectra: only as good as the worse identification. Mol Cell Proteomics 2013; 13:420-34. [PMID: 24335475 DOI: 10.1074/mcp.m113.034009] [Citation(s) in RCA: 136] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Chemical cross-linking mass spectrometry identifies interacting surfaces within a protein assembly through labeling with bifunctional reagents and identifying the covalently modified peptides. These yield distance constraints that provide a powerful means to model the three-dimensional structure of the assembly. Bioinformatic analysis of cross-linked data resulting from large protein assemblies is challenging because each cross-linked product contains two covalently linked peptides, each of which must be correctly identified from a complex matrix of potential confounders. Protein Prospector addresses these issues through a complementary mass modification strategy in which each peptide is searched and identified separately. We demonstrate this strategy with an analysis of RNA polymerase II. False discovery rates (FDRs) are assessed via comparison of cross-linking data to crystal structure, as well as by using a decoy database strategy. Parameters that are most useful for positive identification of cross-linked spectra are explored. We find that fragmentation spectra generally contain more product ions from one of the two peptides constituting the cross-link. Hence, metrics reflecting the quality of the spectral match to the less confident peptide provide the most discriminatory power between correct and incorrect matches. A support vector machine model was built to further improve classification of cross-linked peptide hits. Furthermore, the frequency with which peptides cross-linked via common acylating reagents fragment to produce diagnostic, cross-linker-specific ions is assessed. The threshold for successful identification of the cross-linked peptide product depends upon the complexity of the sample under investigation. Protein Prospector, by focusing the reliability assessment on the least confident peptide, is better able to control the FDR for results as larger complexes and databases are analyzed. In addition, when FDR thresholds are calculated separately for intraprotein and interprotein results, a further improvement in the number of unique cross-links confidently identified is achieved. These improvements are demonstrated on two previously published cross-linking datasets.
Collapse
Affiliation(s)
- Michael J Trnka
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California 94158
| | | | | | | | | |
Collapse
|
24
|
de Val N, McMurray MA, Lam LH, Hsiung CCS, Bertin A, Nogales E, Thorner J. Native cysteine residues are dispensable for the structure and function of all five yeast mitotic septins. Proteins 2013; 81:1964-79. [PMID: 23775754 PMCID: PMC3880206 DOI: 10.1002/prot.24345] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 04/30/2013] [Accepted: 05/31/2013] [Indexed: 01/19/2023]
Abstract
Budding yeast septins assemble into hetero-octamers and filaments required for cytokinesis. Solvent-exposed cysteine (Cys) residues provide sites for attaching substituents useful in assessing assembly kinetics and protein interactions. To introduce Cys at defined locations, site-directed mutagenesis was used, first, to replace the native Cys residues in Cdc3 (C124 C253 C279), Cdc10 (C266), Cdc11 (C43 C137 C138), Cdc12 (C40 C278), and Shs1 (C29 C148) with Ala, Ser, Val, or Phe. When plasmid-expressed, each Cys-less septin mutant rescued the cytokinesis defects caused by absence of the corresponding chromosomal gene. When integrated and expressed from its endogenous promoter, the same mutants were fully functional, except Cys-less Cdc12 mutants (which were viable, but exhibited slow growth and aberrant morphology) and Cdc3(C124V C253V C279V) (which was inviable). No adverse phenotypes were observed when certain pairs of Cys-less septins were co-expressed as the sole source of these proteins. Cells grew less well when three Cys-less septins were co-expressed, suggesting some reduction in fitness. Nonetheless, cells chromosomally expressing Cys-less Cdc10, Cdc11, and Cdc12, and expressing Cys-less Cdc3 from a plasmid, grew well at 30°C. Moreover, recombinant Cys-less septins--or where one of the Cys-less septins contained a single Cys introduced at a new site--displayed assembly properties in vitro indistinguishable from wild-type.
Collapse
Affiliation(s)
- Natalia de Val
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202
| | - Michael A. McMurray
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202
| | - Lisa H. Lam
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202
| | - Chris C.-S. Hsiung
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202
| | - Aurélie Bertin
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202
| | - Eva Nogales
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
- Howard Hughes Medical Institute, 4000 Jones Bridge Road, Chevy Chase, Maryland 20815–6789
| | - Jeremy Thorner
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202
| |
Collapse
|
25
|
Kahraman A, Herzog F, Leitner A, Rosenberger G, Aebersold R, Malmström L. Cross-link guided molecular modeling with ROSETTA. PLoS One 2013; 8:e73411. [PMID: 24069194 PMCID: PMC3775805 DOI: 10.1371/journal.pone.0073411] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 07/19/2013] [Indexed: 11/19/2022] Open
Abstract
Chemical cross-links identified by mass spectrometry generate distance restraints that reveal low-resolution structural information on proteins and protein complexes. The technology to reliably generate such data has become mature and robust enough to shift the focus to the question of how these distance restraints can be best integrated into molecular modeling calculations. Here, we introduce three workflows for incorporating distance restraints generated by chemical cross-linking and mass spectrometry into ROSETTA protocols for comparative and de novo modeling and protein-protein docking. We demonstrate that the cross-link validation and visualization software Xwalk facilitates successful cross-link data integration. Besides the protocols we introduce XLdb, a database of chemical cross-links from 14 different publications with 506 intra-protein and 62 inter-protein cross-links, where each cross-link can be mapped on an experimental structure from the Protein Data Bank. Finally, we demonstrate on a protein-protein docking reference data set the impact of virtual cross-links on protein docking calculations and show that an inter-protein cross-link can reduce on average the RMSD of a docking prediction by 5.0 Å. The methods and results presented here provide guidelines for the effective integration of chemical cross-link data in molecular modeling calculations and should advance the structural analysis of particularly large and transient protein complexes via hybrid structural biology methods.
Collapse
Affiliation(s)
- Abdullah Kahraman
- Department of Biology, Institute of Molecular Systems Biology, Eidgenössische Technische Hochschule Zürich, Zurich, Switzerland
| | - Franz Herzog
- Gene Center, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Alexander Leitner
- Department of Biology, Institute of Molecular Systems Biology, Eidgenössische Technische Hochschule Zürich, Zurich, Switzerland
| | - George Rosenberger
- Department of Biology, Institute of Molecular Systems Biology, Eidgenössische Technische Hochschule Zürich, Zurich, Switzerland
| | - Ruedi Aebersold
- Department of Biology, Institute of Molecular Systems Biology, Eidgenössische Technische Hochschule Zürich, Zurich, Switzerland
- Faculty of Science, University of Zurich, Zurich, Switzerland
| | - Lars Malmström
- Department of Biology, Institute of Molecular Systems Biology, Eidgenössische Technische Hochschule Zürich, Zurich, Switzerland
- * E-mail:
| |
Collapse
|
26
|
Merkley ED, Cort JR, Adkins JN. Cross-linking and mass spectrometry methodologies to facilitate structural biology: finding a path through the maze. ACTA ACUST UNITED AC 2013; 14:77-90. [PMID: 23917845 DOI: 10.1007/s10969-013-9160-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 07/26/2013] [Indexed: 12/12/2022]
Abstract
Multiprotein complexes, rather than individual proteins, make up a large part of the biological macromolecular machinery of a cell. Understanding the structure and organization of these complexes is critical to understanding cellular function. Chemical cross-linking coupled with mass spectrometry is emerging as a complementary technique to traditional structural biology methods and can provide low-resolution structural information for a multitude of purposes, such as distance constraints in computational modeling of protein complexes. In this review, we discuss the experimental considerations for successful application of chemical cross-linking-mass spectrometry in biological studies and highlight three examples of such studies from the recent literature. These examples (as well as many others) illustrate the utility of a chemical cross-linking-mass spectrometry approach in facilitating structural analysis of large and challenging complexes.
Collapse
Affiliation(s)
- Eric D Merkley
- MS K8-98, Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
| | | | | |
Collapse
|
27
|
Paramelle D, Miralles G, Subra G, Martinez J. Chemical cross-linkers for protein structure studies by mass spectrometry. Proteomics 2013; 13:438-56. [PMID: 23255214 DOI: 10.1002/pmic.201200305] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 10/12/2012] [Accepted: 10/22/2012] [Indexed: 12/24/2022]
Abstract
The cross-linking approach combined with MS for protein structure determination is one of the most striking examples of multidisciplinary success. Indeed, it has become clear that the bottleneck of the method was the detection and the identification of low-abundance cross-linked peptides in complex mixtures. Sample treatment or chromatography separation partially addresses these issues. However, the main problem comes from over-represented unmodified peptides, which do not yield any structural information. A real breakthrough was provided by high mass accuracy measurement, because of the outstanding technical developments in MS. This improvement greatly simplified the identification of cross-linked peptides, reducing the possible combinations matching with an observed m/z value. In addition, the huge amount of data collected has to be processed with dedicated software whose role is to propose distance constraints or ideally a structural model of the protein. In addition to instrumentation and algorithms efficiency, significant efforts have been made to design new cross-linkers matching all the requirements in terms of reactivity and selectivity but also displaying probes or reactive systems facilitating the isolation, the detection of cross-links, or the interpretation of MS data. These chemical features are reviewed and commented on in the light of the more recent strategies.
Collapse
Affiliation(s)
- David Paramelle
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 3 Research Link, Singapore
| | | | | | | |
Collapse
|
28
|
Zybailov BL, Glazko GV, Jaiswal M, Raney KD. Large Scale Chemical Cross-linking Mass Spectrometry Perspectives. ACTA ACUST UNITED AC 2013; 6:001. [PMID: 25045217 PMCID: PMC4101816 DOI: 10.4172/jpb.s2-001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The spectacular heterogeneity of a complex protein mixture from biological samples becomes even more difficult to tackle when one’s attention is shifted towards different protein complex topologies, transient interactions, or localization of PPIs. Meticulous protein-by-protein affinity pull-downs and yeast-two-hybrid screens are the two approaches currently used to decipher proteome-wide interaction networks. Another method is to employ chemical cross-linking, which gives not only identities of interactors, but could also provide information on the sites of interactions and interaction interfaces. Despite significant advances in mass spectrometry instrumentation over the last decade, mapping Protein-Protein Interactions (PPIs) using chemical cross-linking remains time consuming and requires substantial expertise, even in the simplest of systems. While robust methodologies and software exist for the analysis of binary PPIs and also for the single protein structure refinement using cross-linking-derived constraints, undertaking a proteome-wide cross-linking study is highly complex. Difficulties include i) identifying cross-linkers of the right length and selectivity that could capture interactions of interest; ii) enrichment of the cross-linked species; iii) identification and validation of the cross-linked peptides and cross-linked sites. In this review we examine existing literature aimed at the large-scale protein cross-linking and discuss possible paths for improvement. We also discuss short-length cross-linkers of broad specificity such as formaldehyde and diazirine-based photo-cross-linkers. These cross-linkers could potentially capture many types of interactions, without strict requirement for a particular amino-acid to be present at a given protein-protein interface. How these shortlength, broad specificity cross-linkers be applied to proteome-wide studies? We will suggest specific advances in methodology, instrumentation and software that are needed to make such a leap.
Collapse
Affiliation(s)
- Boris L Zybailov
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Galina V Glazko
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Mihir Jaiswal
- UALR/UAMS Joint Bioinformatics Program, University of Arkansas Little Rock, Little Rock, AR, USA
| | - Kevin D Raney
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| |
Collapse
|
29
|
RNA polymerase III subunit architecture and implications for open promoter complex formation. Proc Natl Acad Sci U S A 2012; 109:19232-7. [PMID: 23132938 DOI: 10.1073/pnas.1211665109] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Transcription initiation by eukaryotic RNA polymerase (Pol) III relies on the TFIIE-related subcomplex C82/34/31. Here we combine cross-linking and hydroxyl radical probing to position the C82/34/31 subcomplex around the Pol III active center cleft. The extended winged helix (WH) domains 1 and 4 of C82 localize to the polymerase domains clamp head and clamp core, respectively, and the two WH domains of C34 span the polymerase cleft from the coiled-coil region of the clamp to the protrusion. The WH domains of C82 and C34 apparently cooperate with other mobile regions flanking the cleft during promoter DNA binding, opening, and loading. Together with published data, our results complete the subunit architecture of Pol III and indicate that all TFIIE-related components of eukaryotic and archaeal transcription systems adopt an evolutionarily conserved location in the upper part of the cleft that supports their functions in open promoter complex formation and stabilization.
Collapse
|
30
|
Diversity in genetic in vivo methods for protein-protein interaction studies: from the yeast two-hybrid system to the mammalian split-luciferase system. Microbiol Mol Biol Rev 2012; 76:331-82. [PMID: 22688816 DOI: 10.1128/mmbr.05021-11] [Citation(s) in RCA: 134] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The yeast two-hybrid system pioneered the field of in vivo protein-protein interaction methods and undisputedly gave rise to a palette of ingenious techniques that are constantly pushing further the limits of the original method. Sensitivity and selectivity have improved because of various technical tricks and experimental designs. Here we present an exhaustive overview of the genetic approaches available to study in vivo binary protein interactions, based on two-hybrid and protein fragment complementation assays. These methods have been engineered and employed successfully in microorganisms such as Saccharomyces cerevisiae and Escherichia coli, but also in higher eukaryotes. From single binary pairwise interactions to whole-genome interactome mapping, the self-reassembly concept has been employed widely. Innovative studies report the use of proteins such as ubiquitin, dihydrofolate reductase, and adenylate cyclase as reconstituted reporters. Protein fragment complementation assays have extended the possibilities in protein-protein interaction studies, with technologies that enable spatial and temporal analyses of protein complexes. In addition, one-hybrid and three-hybrid systems have broadened the types of interactions that can be studied and the findings that can be obtained. Applications of these technologies are discussed, together with the advantages and limitations of the available assays.
Collapse
|
31
|
Grünberg S, Warfield L, Hahn S. Architecture of the RNA polymerase II preinitiation complex and mechanism of ATP-dependent promoter opening. Nat Struct Mol Biol 2012; 19:788-96. [PMID: 22751016 PMCID: PMC3414687 DOI: 10.1038/nsmb.2334] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 05/28/2012] [Indexed: 01/23/2023]
Abstract
Yeast RNA polymerase (Pol) II general factor TFIIE and the TFIIH subunit Ssl2/XPB function in transition of the preinitiation complex (PIC) to the open complex. We find that the three TFIIE winged helix (WH) domains form a heterodimer, with the Tfa1/TFIIEα WH binding the Pol II clamp and the Tfa2/TFIIEβ tandem WH domain encircling promoter DNA that becomes single stranded in the open complex. Ssl2 lies adjacent to TFIIE, enclosing downstream promoter DNA. In contrast to previous proposals, comparison of the PIC and open complex models strongly suggests that Ssl2 promotes DNA opening by functioning as a double stranded DNA translocase, feeding 15 bp of double stranded DNA into the Pol II cleft. Right-handed threading of DNA through the Ssl2 binding groove, combined with the fixed position of upstream promoter DNA, will lead to DNA unwinding and the open state.
Collapse
|