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Chang TH, Hsieh FL, Gu X, Smallwood PM, Kavran JM, Gabelli SB, Nathans J. Structural insights into plasmalemma vesicle-associated protein (PLVAP): Implications for vascular endothelial diaphragms and fenestrae. Proc Natl Acad Sci U S A 2023; 120:e2221103120. [PMID: 36996108 PMCID: PMC10083539 DOI: 10.1073/pnas.2221103120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 02/20/2023] [Indexed: 03/31/2023] Open
Abstract
In many organs, small openings across capillary endothelial cells (ECs) allow the diffusion of low-molecular weight compounds and small proteins between the blood and tissue spaces. These openings contain a diaphragm composed of radially arranged fibers, and current evidence suggests that a single-span type II transmembrane protein, plasmalemma vesicle-associated protein-1 (PLVAP), constitutes these fibers. Here, we present the three-dimensional crystal structure of an 89-amino acid segment of the PLVAP extracellular domain (ECD) and show that it adopts a parallel dimeric alpha-helical coiled-coil configuration with five interchain disulfide bonds. The structure was solved using single-wavelength anomalous diffraction from sulfur-containing residues (sulfur SAD) to generate phase information. Biochemical and circular dichroism (CD) experiments show that a second PLVAP ECD segment also has a parallel dimeric alpha-helical configuration-presumably a coiled coil-held together with interchain disulfide bonds. Overall, ~2/3 of the ~390 amino acids within the PLVAP ECD adopt a helical configuration, as determined by CD. We also determined the sequence and epitope of MECA-32, an anti-PLVAP antibody. Taken together, these data lend strong support to the model of capillary diaphragms formulated by Tse and Stan in which approximately ten PLVAP dimers are arranged within each 60- to 80-nm-diameter opening like the spokes of a bicycle wheel. Passage of molecules through the wedge-shaped pores is presumably determined both by the length of PLVAP-i.e., the long dimension of the pore-and by the chemical properties of amino acid side chains and N-linked glycans on the solvent-accessible faces of PLVAP.
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Affiliation(s)
- Tao-Hsin Chang
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD21205
- HHMI, Johns Hopkins University School of Medicine, Baltimore, MD21205
| | - Fu-Lien Hsieh
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD21205
- HHMI, Johns Hopkins University School of Medicine, Baltimore, MD21205
| | - Xiaowu Gu
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD21205
- HHMI, Johns Hopkins University School of Medicine, Baltimore, MD21205
| | - Philip M. Smallwood
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD21205
- HHMI, Johns Hopkins University School of Medicine, Baltimore, MD21205
| | - Jennifer M. Kavran
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD21205
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD21205
| | - Sandra B. Gabelli
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD21205
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD21205
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD21205
| | - Jeremy Nathans
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD21205
- HHMI, Johns Hopkins University School of Medicine, Baltimore, MD21205
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD21205
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD21205
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2
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Mou TC, Zeng B, Doukov TI, Sprang SR. Application of sulfur SAD to small crystals with a large asymmetric unit and anomalous substructure. Acta Crystallogr D Struct Biol 2022; 78:1021-1031. [PMID: 35916226 PMCID: PMC9344479 DOI: 10.1107/s2059798322005848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 05/31/2022] [Indexed: 11/17/2022] Open
Abstract
The application of sulfur single-wavelength anomalous dispersion (S-SAD) to determine the crystal structures of macromolecules can be challenging if the asymmetric unit is large, the crystals are small, the size of the anomalously scattering sulfur structure is large and the resolution at which the anomalous signals can be accurately measured is modest. Here, as a study of such a case, approaches to the SAD phasing of orthorhombic Ric-8A crystals are described. The structure of Ric-8A was published with only a brief description of the phasing process [Zeng et al. (2019), Structure, 27, 1137-1141]. Here, alternative approaches to determining the 40-atom sulfur substructure of the 103 kDa Ric-8A dimer that composes the asymmetric unit are explored. At the data-collection wavelength of 1.77 Å measured at the Frontier micro-focusing Macromolecular Crystallography (FMX) beamline at National Synchrotron Light Source II, the sulfur anomalous signal strength, |Δano|/σΔano (d''/sig), approaches 1.4 at 3.4 Å resolution. The highly redundant, 11 000 000-reflection data set measured from 18 crystals was segmented into isomorphous clusters using BLEND in the CCP4 program suite. Data sets within clusters or sets of clusters were scaled and merged using AIMLESS from CCP4 or, alternatively, the phenix.scale_and_merge tool from the Phenix suite. The latter proved to be the more effective in extracting anomalous signals. The HySS tool in Phenix, SHELXC/D and PRASA as implemented in the CRANK2 program suite were each employed to determine the sulfur substructure. All of these approaches were effective, although HySS, as a component of the phenix.autosol tool, required data from all crystals to find the positions of the sulfur atoms. Critical contributors in this case study to successful phase determination by SAD included (i) the high-flux FMX beamline, featuring helical-mode data collection and a helium-filled beam path, (ii) as recognized by many authors, a very highly redundant, multiple-crystal data set and (iii) the inclusion within that data set of data from crystals that were scanned over large ω ranges, yielding highly isomorphous and highly redundant intensity measurements.
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Affiliation(s)
- Tung Chung Mou
- Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, MT 59812, USA
| | - Baisen Zeng
- Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, MT 59812, USA
| | - Tzanko I Doukov
- Macromolecular Crystallography Group, Stanford Synchrotron Radiation Light Source, SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94309, USA
| | - Stephen R Sprang
- Center for Biomolecular Structure and Dynamics, University of Montana, Missoula, MT 59812, USA
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3
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Hatti KS, McCoy AJ, Read RJ. Likelihood-based estimation of substructure content from single-wavelength anomalous diffraction (SAD) intensity data. Acta Crystallogr D Struct Biol 2021; 77:880-893. [PMID: 34196615 PMCID: PMC8251343 DOI: 10.1107/s2059798321004538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 04/28/2021] [Indexed: 11/14/2022] Open
Abstract
SAD phasing can be challenging when the signal-to-noise ratio is low. In such cases, having an accurate estimate of the substructure content can determine whether or not the substructure of anomalous scatterer positions can successfully be determined. Here, a likelihood-based target function is proposed to accurately estimate the strength of the anomalous scattering contribution directly from the measured intensities, determining a complex correlation parameter relating the Bijvoet mates as a function of resolution. This gives a novel measure of the intrinsic anomalous signal. The SAD likelihood target function also accounts for correlated errors in the measurement of intensities from Bijvoet mates, which can arise from the effects of radiation damage. When the anomalous signal is assumed to come primarily from a substructure comprising one anomalous scatterer with a known value of f'' and when the protein composition of the crystal is estimated correctly, the refined complex correlation parameters can be interpreted in terms of the atomic content of the primary anomalous scatterer before the substructure is known. The maximum-likelihood estimation of substructure content was tested on a curated database of 357 SAD cases with useful anomalous signal. The prior estimates of substructure content are highly correlated to the content determined by phasing calculations, with a correlation coefficient (on a log-log basis) of 0.72.
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Affiliation(s)
- Kaushik S. Hatti
- Cambridge Institute for Medical Research, Department of Haematology, University of Cambridge, The Keith Peters Building, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Airlie J. McCoy
- Cambridge Institute for Medical Research, Department of Haematology, University of Cambridge, The Keith Peters Building, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Randy J. Read
- Cambridge Institute for Medical Research, Department of Haematology, University of Cambridge, The Keith Peters Building, Hills Road, Cambridge CB2 0XY, United Kingdom
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4
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Zwart PH, Perryman ED. Evaluating crystallographic likelihood functions using numerical quadratures. Acta Crystallogr D Struct Biol 2020; 76:736-750. [PMID: 32744256 PMCID: PMC7397490 DOI: 10.1107/s2059798320008372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 06/23/2020] [Indexed: 12/02/2022] Open
Abstract
Intensity-based likelihood functions in crystallographic applications have the potential to enhance the quality of structures derived from marginal diffraction data. Their usage, however, is complicated by the ability to efficiently compute these target functions. Here, a numerical quadrature is developed that allows the rapid evaluation of intensity-based likelihood functions in crystallographic applications. By using a sequence of change-of-variable transformations, including a nonlinear domain-compression operation, an accurate, robust and efficient quadrature is constructed. The approach is flexible and can incorporate different noise models with relative ease.
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Affiliation(s)
- Petrus H. Zwart
- Center for Advanced Mathematics in Energy Research Applications, Computational Research Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
- Molecular Biophysics and Integrative Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Elliott D. Perryman
- Center for Advanced Mathematics in Energy Research Applications, Computational Research Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
- Molecular Biophysics and Integrative Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
- The University of Tennessee at Knoxville, Knoxville, TN 37916, USA
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5
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Alharbi E, Bond PS, Calinescu R, Cowtan K. Comparison of automated crystallographic model-building pipelines. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2019; 75:1119-1128. [PMID: 31793905 DOI: 10.1107/s2059798319014918] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 11/04/2019] [Indexed: 11/10/2022]
Abstract
A comparison of four protein model-building pipelines (ARP/wARP, Buccaneer, PHENIX AutoBuild and SHELXE) was performed using data sets from 202 experimentally phased cases, both with the data as observed and truncated to simulate lower resolutions. All pipelines were run using default parameters. Additionally, an ARP/wARP run was completed using models from Buccaneer. All pipelines achieved nearly complete protein structures and low Rwork/Rfree at resolutions between 1.2 and 1.9 Å, with PHENIX AutoBuild and ARP/wARP producing slightly lower R factors. At lower resolutions, Buccaneer leads to significantly more complete models.
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Affiliation(s)
- Emad Alharbi
- Department of Computer Science, University of York, Heslington, York YO10 5GH, England
| | - Paul S Bond
- Department of Chemistry, University of York, Heslington, York YO10 5DD, England
| | - Radu Calinescu
- Department of Computer Science, University of York, Heslington, York YO10 5GH, England
| | - Kevin Cowtan
- Department of Chemistry, University of York, Heslington, York YO10 5DD, England
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6
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Brewster AS, Bhowmick A, Bolotovsky R, Mendez D, Zwart PH, Sauter NK. SAD phasing of XFEL data depends critically on the error model. Acta Crystallogr D Struct Biol 2019; 75:959-968. [PMID: 31692470 PMCID: PMC6834081 DOI: 10.1107/s2059798319012877] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 09/17/2019] [Indexed: 11/11/2022] Open
Abstract
A nonlinear least-squares method for refining a parametric expression describing the estimated errors of reflection intensities in serial crystallographic (SX) data is presented. This approach, which is similar to that used in the rotation method of crystallographic data collection at synchrotrons, propagates error estimates from photon-counting statistics to the merged data. Here, it is demonstrated that the application of this approach to SX data provides better SAD phasing ability, enabling the autobuilding of a protein structure that had previously failed to be built. Estimating the error in the merged reflection intensities requires the understanding and propagation of all of the sources of error arising from the measurements. One type of error, which is well understood, is the counting error introduced when the detector counts X-ray photons. Thus, if other types of random errors (such as readout noise) as well as uncertainties in systematic corrections (such as from X-ray attenuation) are completely understood, they can be propagated along with the counting error, as appropriate. In practice, most software packages propagate as much error as they know how to model and then include error-adjustment terms that scale the error estimates until they explain the variance among the measurements. If this is performed carefully, then during SAD phasing likelihood-based approaches can make optimal use of these error estimates, increasing the chance of a successful structure solution. In serial crystallography, SAD phasing has remained challenging, with the few examples of de novo protein structure solution each requiring many thousands of diffraction patterns. Here, the effects of different methods of treating the error estimates are estimated and it is shown that using a parametric approach that includes terms proportional to the known experimental uncertainty, the reflection intensity and the squared reflection intensity to improve the error estimates can allow SAD phasing even from weak zinc anomalous signal.
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Affiliation(s)
- Aaron S. Brewster
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Asmit Bhowmick
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Robert Bolotovsky
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Derek Mendez
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Petrus H. Zwart
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Center for Advanced Mathematics for Energy Research Applications, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Nicholas K. Sauter
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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7
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Chen Y, Wang L, Shang F, Liu W, Lan J, Chen J, Ha NC, Quan C, Nam KH, Xu Y. Structural insight of the 5-(Hydroxyethyl)-methylthiazole kinase ThiM involving vitamin B1 biosynthetic pathway from the Klebsiella pneumoniae. Biochem Biophys Res Commun 2019; 518:513-518. [PMID: 31439375 DOI: 10.1016/j.bbrc.2019.08.086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 08/14/2019] [Indexed: 01/08/2023]
Abstract
Thiamin pyrophosphate (TPP) is an essential co-factor in amino acid and carbohydrate metabolic pathways. The TPP-related vitamin B1 biosynthetic pathway is found in most bacterial, plant and lower eukaryotic processes; however, it is not present in humans. In bacterial thiamin synthesis and salvage pathways, the 5-(hydroxyethyl)-methylthiazole kinase (ThiM) is essential in the pathway forming TPP. Thus, ThiM is considered to be an attractive antibacterial drug target. Here, we determined the crystal structures of ThiM from pathogenic Klebsiella pneumoniae (KpThiM) and KpThiM in complex with its substrate 5-(hydroxyethyl)-4-methylthiazole (TZE). KpThiM, consisting of an α-β-α domain, shows a pseudosymmetric trimeric formation. TZE molecules are located in the interface between the KpThiM subunits in the trimer and interact with Met49 and Cys200. Superimposition of the apo and TZE-complexed structures of KpThiM show that the side chains of the amino acids interacting with TZE and Mg2+ have a rigid configuration. Comparison of the ThiM structures shows that KpThiM could, in terms of sequence and configuration, be different from other ThiM proteins, which possess different amino acids that recognize TZE and Mg2+. The structures will provide new insight into the ThiM subfamily proteins for antibacterial drug development.
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Affiliation(s)
- Yuanyuan Chen
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian, 116600, Liaoning, China; Key Laboratory of Biotechnology and Bioresources Utilization (Dalian Minzu University), Ministry of Education, China
| | - Lulu Wang
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian, 116600, Liaoning, China; Key Laboratory of Biotechnology and Bioresources Utilization (Dalian Minzu University), Ministry of Education, China; School of Life Science and Biotechnology, Dalian University of Technology, No 2 Linggong Road, Dalian, 116024, Liaoning, China
| | - Fei Shang
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian, 116600, Liaoning, China; Key Laboratory of Biotechnology and Bioresources Utilization (Dalian Minzu University), Ministry of Education, China
| | - Wei Liu
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian, 116600, Liaoning, China; Key Laboratory of Biotechnology and Bioresources Utilization (Dalian Minzu University), Ministry of Education, China
| | - Jing Lan
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian, 116600, Liaoning, China; Key Laboratory of Biotechnology and Bioresources Utilization (Dalian Minzu University), Ministry of Education, China
| | - Jinli Chen
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian, 116600, Liaoning, China; Key Laboratory of Biotechnology and Bioresources Utilization (Dalian Minzu University), Ministry of Education, China
| | - Nam-Chul Ha
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Chunshan Quan
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian, 116600, Liaoning, China; Key Laboratory of Biotechnology and Bioresources Utilization (Dalian Minzu University), Ministry of Education, China.
| | - Ki Hyun Nam
- Division of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, 02841, Republic of Korea; Institute of Life Science and Natural Resources, Korea University, Seoul, 02841, Republic of Korea.
| | - Yongbin Xu
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian, 116600, Liaoning, China; Key Laboratory of Biotechnology and Bioresources Utilization (Dalian Minzu University), Ministry of Education, China.
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8
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Saotome M, Horikoshi N, Urano K, Kujirai T, Yuzurihara H, Kurumizaka H, Kagawa W. Structure determination of the nucleosome core particle by selenium SAD phasing. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2019; 75:930-936. [PMID: 31588924 DOI: 10.1107/s2059798319012713] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 09/12/2019] [Indexed: 11/10/2022]
Abstract
The eukaryotic genome is compacted inside the nucleus of the cell in the form called chromatin. The fundamental unit of chromatin is the nucleosome, which contains four types of histones (H3, H4, H2A and H2B) and approximately 150 base pairs of DNA wrapped around the histone complex. The structure of the nucleosome is highly conserved across several eukaryotic species, and molecular replacement has been the primary phasing method used to solve nucleosome structures by X-ray crystallography. However, there is currently no simple, widely applicable experimental phasing method for the nucleosome. In the present study, it is demonstrated that selenomethionine-incorporated histones H3, H2A and H2B can be reconstituted into nucleosomes and crystallized for structural determination. Unexpectedly, it was found that the nucleosome can be phased with a relatively small number of Se atoms. The structures of nucleosome core particles containing 12 and 16 Se atoms were solved by SAD phasing at 2.5 and 2.4 Å resolution, respectively. The present study demonstrates a simple method for determining nucleosome structures by experimental phasing, which may be particularly useful for noncanonical structures that cannot be solved by molecular replacement.
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Affiliation(s)
- Mika Saotome
- Department of Chemistry, Graduate School of Science and Engineering, Meisei University, 2-1-1 Hodokubo, Hino-shi, Tokyo 191-8506, Japan
| | - Naoki Horikoshi
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Kazuki Urano
- Department of Chemistry, Graduate School of Science and Engineering, Meisei University, 2-1-1 Hodokubo, Hino-shi, Tokyo 191-8506, Japan
| | - Tomoya Kujirai
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Hidetaka Yuzurihara
- Department of Chemistry, Graduate School of Science and Engineering, Meisei University, 2-1-1 Hodokubo, Hino-shi, Tokyo 191-8506, Japan
| | - Hitoshi Kurumizaka
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
| | - Wataru Kagawa
- Department of Chemistry, Graduate School of Science and Engineering, Meisei University, 2-1-1 Hodokubo, Hino-shi, Tokyo 191-8506, Japan
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9
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Guo G, Zhu P, Fuchs MR, Shi W, Andi B, Gao Y, Hendrickson WA, McSweeney S, Liu Q. Synchrotron microcrystal native-SAD phasing at a low energy. IUCRJ 2019; 6:532-542. [PMID: 31316798 PMCID: PMC6608635 DOI: 10.1107/s2052252519004536] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 04/03/2019] [Indexed: 05/31/2023]
Abstract
De novo structural evaluation of native biomolecules from single-wavelength anomalous diffraction (SAD) is a challenge because of the weakness of the anomalous scattering. The anomalous scattering from relevant native elements - primarily sulfur in proteins and phospho-rus in nucleic acids - increases as the X-ray energy decreases toward their K-edge transitions. Thus, measurements at a lowered X-ray energy are promising for making native SAD routine and robust. For microcrystals with sizes less than 10 µm, native-SAD phasing at synchrotron microdiffraction beamlines is even more challenging because of difficulties in sample manipulation, diffraction data collection and data analysis. Native-SAD analysis from microcrystals by using X-ray free-electron lasers has been demonstrated but has required use of thousands of thousands of microcrystals to achieve the necessary accuracy. Here it is shown that by exploitation of anomalous microdiffraction signals obtained at 5 keV, by the use of polyimide wellmounts, and by an iterative crystal and frame-rejection method, microcrystal native-SAD phasing is possible from as few as about 1 200 crystals. Our results show the utility of low-energy native-SAD phasing with microcrystals at synchrotron microdiffraction beamlines.
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Affiliation(s)
- Gongrui Guo
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA
- Photon Science, NSLS-II, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Ping Zhu
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Martin R. Fuchs
- Photon Science, NSLS-II, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Wuxian Shi
- Photon Science, NSLS-II, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Babak Andi
- Photon Science, NSLS-II, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Yuan Gao
- Photon Science, NSLS-II, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Wayne A. Hendrickson
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA
| | - Sean McSweeney
- Photon Science, NSLS-II, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Qun Liu
- Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA
- Photon Science, NSLS-II, Brookhaven National Laboratory, Upton, NY 11973, USA
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10
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Gourdoupis S, Nasta V, Ciofi-Baffoni S, Banci L, Calderone V. In-house high-energy-remote SAD phasing using the magic triangle: how to tackle the P1 low symmetry using multiple orientations of the same crystal of human IBA57 to increase the multiplicity. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2019; 75:317-324. [DOI: 10.1107/s2059798319000214] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 01/04/2019] [Indexed: 11/10/2022]
Abstract
This article describes the approach used to solve the structure of human IBA57 in-house by 5-amino-2,4,6-triiodoisophthalic acid (I3C) high-energy-remote single-wavelength anomalous dispersion (SAD) phasing. Multiple orientations of the same triclinic crystal were exploited to acquire sufficient real data multiplicity for phasing. How the collection of an in-house native data set and its joint use with the I3C derivative through a SIRAS approach decreases the data multiplicity needed by almost 50% is described. Furthermore, it is illustrated that there is a clear data-multiplicity threshold value for success and failure in phasing, and how adding further data does not significantly affect substructure solution and model building. To our knowledge, this is the only structure present in the PDB that has been solved in-house by remote SAD phasing in space group P1 using only one crystal. All of the raw data used, derived from the different orientations, have been uploaded to Zenodo in order to enable software developers to improve methods for data processing and structure solution, and for educational purposes.
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11
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Read RJ, McCoy AJ. Maximum-likelihood determination of anomalous substructures. Acta Crystallogr D Struct Biol 2018; 74:98-105. [PMID: 29533235 PMCID: PMC5947773 DOI: 10.1107/s2059798317013468] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 09/20/2017] [Indexed: 11/10/2022] Open
Abstract
A fast Fourier transform (FFT) method is described for determining the substructure of anomalously scattering atoms in macromolecular crystals that allows successful structure determination by X-ray single-wavelength anomalous diffraction (SAD). This method is based on the maximum-likelihood SAD phasing function, which accounts for measurement errors and for correlations between the observed and calculated Bijvoet mates. Proof of principle is shown that this method can improve determination of the anomalously scattering substructure in challenging cases where the anomalous scattering from the substructure is weak but the substructure also constitutes a significant fraction of the real scattering. The method is deterministic and can be fast compared with existing multi-trial dual-space methods for SAD substructure determination.
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Affiliation(s)
- Randy J. Read
- Department of Haematology, University of Cambridge, Hills Road, Cambridge CB2 0XY, England
| | - Airlie J. McCoy
- Department of Haematology, University of Cambridge, Hills Road, Cambridge CB2 0XY, England
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12
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Usón I, Sheldrick GM. An introduction to experimental phasing of macromolecules illustrated by SHELX; new autotracing features. Acta Crystallogr D Struct Biol 2018; 74:106-116. [PMID: 29533236 PMCID: PMC5947774 DOI: 10.1107/s2059798317015121] [Citation(s) in RCA: 114] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 10/17/2017] [Indexed: 11/10/2022] Open
Abstract
For the purpose of this article, experimental phasing is understood to mean the determination of macromolecular structures by exploiting small intensity differences of Friedel opposites and possibly of reflections measured at different wavelengths or for heavy-atom derivatives, without the use of specific structural models. The SHELX programs provide a robust and efficient route for routine structure solution by the SAD, MAD and related methods, but involve a number of simplifying assumptions that may limit their applicability in borderline cases. The substructure atoms (i.e. those with significant anomalous scattering) are first located by direct methods, and the experimental data are then used to estimate phase shifts that are added to the substructure phases to obtain starting phases for the native reflections. These are then improved by density modification and, if the resolution of the data and the type of structure permit, polyalanine tracing. A number of extensions to the tracing algorithm are discussed; these are designed to improve its performance at low resolution. Given native data to 2.5 Å resolution or better, a correlation coefficient greater than 25% between the structure factors calculated from such a trace and the native data is usually a good indication that the structure has been solved.
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Affiliation(s)
- Isabel Usón
- Structural Biology, IBMB–CSIC, Baldiri Reixach 13-15, 08028 Barcelona, Spain
- ICREA, Baldiri Pg. Lluís Companys 23, 08010 Barcelona, Spain
| | - George M. Sheldrick
- Department of Structural Chemistry, Georg-August Universität Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany
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13
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Wang SZ, Zhang YH, Ren H, Wang YL, Jiang W, Fang BS. Strategies and perspectives of assembling multi-enzyme systems. Crit Rev Biotechnol 2017; 37:1024-1037. [PMID: 28423958 DOI: 10.1080/07388551.2017.1303803] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Multi-enzyme complexes have the potential to achieve high catalytic efficiency for sequence reactions due to their advantages in eliminating product inhibition, facilitating intermediate transfer and in situ regenerating cofactors. Constructing functional multi-enzyme systems to mimic natural multi-enzyme complexes is of great interest for multi-enzymatic biosynthesis and cell-free synthetic biotransformation, but with many challenges. Currently, various assembly strategies have been developed based on the interaction of biomacromolecules such as DNA, peptide and scaffolding protein. On the other hand, chemical-induced assembly is based on the affinity of enzymes with small molecules including inhibitors, cofactors and metal ions has the advantage of simplicity, site-to-site oriented structure control and economy. This review summarizes advances and progresses employing these strategies. Furthermore, challenges and perspectives in designing multi-enzyme systems are highlighted.
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Affiliation(s)
- Shi-Zhen Wang
- a Department of Chemical and Biochemical Engineering , College of Chemistry and Chemical Engineering, Xiamen University , Xiamen , China.,b The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University , Xiamen , China.,c State-Province Joint Engineering Laboratory of Marine Bioproducts and Technology, Xiamen University , Xiamen , China
| | - Yong-Hui Zhang
- a Department of Chemical and Biochemical Engineering , College of Chemistry and Chemical Engineering, Xiamen University , Xiamen , China
| | - Hong Ren
- a Department of Chemical and Biochemical Engineering , College of Chemistry and Chemical Engineering, Xiamen University , Xiamen , China
| | - Ya-Li Wang
- a Department of Chemical and Biochemical Engineering , College of Chemistry and Chemical Engineering, Xiamen University , Xiamen , China
| | - Wei Jiang
- a Department of Chemical and Biochemical Engineering , College of Chemistry and Chemical Engineering, Xiamen University , Xiamen , China
| | - Bai-Shan Fang
- a Department of Chemical and Biochemical Engineering , College of Chemistry and Chemical Engineering, Xiamen University , Xiamen , China.,b The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University , Xiamen , China.,d The Key Laboratory for Chemical Biology of Fujian Province, Xiamen University , Xiamen , China
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14
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Hegde RP, Fedorov AA, Sauder JM, Burley SK, Almo SC, Ramagopal UA. The hidden treasure in your data: phasing with unexpected weak anomalous scatterers from routine data sets. Acta Crystallogr F Struct Biol Commun 2017; 73:184-195. [PMID: 28368276 PMCID: PMC5379167 DOI: 10.1107/s2053230x17002680] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 02/16/2017] [Indexed: 12/25/2022] Open
Abstract
Single-wavelength anomalous dispersion (SAD) utilizing anomalous signal from native S atoms, or other atoms with Z ≤ 20, generally requires highly redundant data collected using relatively long-wavelength X-rays. Here, the results from two proteins are presented where the anomalous signal from serendipitously acquired surface-bound Ca atoms with an anomalous data multiplicity of around 10 was utilized to drive de novo structure determination. In both cases, the Ca atoms were acquired from the crystallization solution, and the data-collection strategy was not optimized to exploit the anomalous signal from these scatterers. The X-ray data were collected at 0.98 Å wavelength in one case and at 1.74 Å in the other (the wavelength was optimized for sulfur, but the anomalous signal from calcium was exploited for structure solution). Similarly, using a test case, it is shown that data collected at ∼1.0 Å wavelength, where the f'' value for sulfur is 0.28 e, are sufficient for structure determination using intrinsic S atoms from a strongly diffracting crystal. Interestingly, it was also observed that SHELXD was capable of generating a substructure solution from high-exposure data with a completeness of 70% for low-resolution reflections extending to 3.5 Å resolution with relatively low anomalous multiplicity. Considering the fact that many crystallization conditions contain anomalous scatterers such as Cl, Ca, Mn etc., checking for the presence of fortuitous anomalous signal in data from well diffracting crystals could prove useful in either determining the structure de novo or in accurately assigning surface-bound atoms.
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Affiliation(s)
- Raghurama P. Hegde
- Division of Biological Sciences, Poornaprajna Institute of Scientific Research, #4, 16th Cross, Sadashivnagar, Bangalore 560 080, India
| | - Alexander A. Fedorov
- Department of Biochemistry, Albert Einstein College of Medicine, Ullmann Building, Jack and Pearl Resnick Campus, 1300 Morris Park Avenue, Bronx, New York, NY 10461, USA
| | - J. Michael Sauder
- Lilly Biotechnology Center, Eli Lilly and Company, 10290 Campus Point Drive, San Diego, CA 92121, USA
| | - Stephen K. Burley
- RCSB Protein Data Bank, Center for Integrative Proteomics Research, Rutgers University, The State University of New Jersey, 174 Frelinghuysen Road, Piscataway, NJ 08854, USA
- Institute of Quantitative Biomedicine, Rutgers University, The State University of New Jersey, Piscataway, NJ 08854, USA
- Rutgers Cancer Institute of New Jersey, Rutgers University, The State University of New Jersey, New Brunswick, NJ 08903, USA
- RCSB Protein Data Bank, San Diego Supercomputer Center, San Diego, California, USA
- Skaggs School of Pharmacy and Pharmceutical Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Steven C. Almo
- Department of Biochemistry, Albert Einstein College of Medicine, Ullmann Building, Jack and Pearl Resnick Campus, 1300 Morris Park Avenue, Bronx, New York, NY 10461, USA
| | - Udupi A. Ramagopal
- Division of Biological Sciences, Poornaprajna Institute of Scientific Research, #4, 16th Cross, Sadashivnagar, Bangalore 560 080, India
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15
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Liu Q, Hendrickson WA. Contemporary Use of Anomalous Diffraction in Biomolecular Structure Analysis. Methods Mol Biol 2017; 1607:377-399. [PMID: 28573582 DOI: 10.1007/978-1-4939-7000-1_16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The normal elastic X-ray scattering that depends only on electron density can be modulated by an "anomalous" component due to resonance between X-rays and electronic orbitals. Anomalous scattering thereby precisely identifies atomic species, since orbitals distinguish atomic elements, which enables the multi- and single-wavelength anomalous diffraction (MAD and SAD) methods. SAD now predominates in de novo structure determination of biological macromolecules, and we focus here on the prevailing SAD method. We describe the anomalous phasing theory and the periodic table of phasing elements that are available for SAD experiments, differentiating between those readily accessible for at-resonance experiments and those that can be effective away from an edge. We describe procedures for present-day SAD phasing experiments and we discuss optimization of anomalous signals for challenging applications. We also describe methods for using anomalous signals as molecular markers for tracing and element identification. Emerging developments and perspectives are discussed in brief.
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Affiliation(s)
- Qun Liu
- Biology Department, Brookhaven National Laboratory, PO Box 5000, 50 Bell Ave, Building 463, Upton, NY, 11973, USA.
| | - Wayne A Hendrickson
- Department of Biochemistry and Molecular Biophysics, Columbia University, 202 Black Building, 650 West 168th Street, New York, NY, 10032, USA.
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16
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Yu LJ, Kawakami T, Kimura Y, Wang-Otomo ZY. Structural Basis for the Unusual Q y Red-Shift and Enhanced Thermostability of the LH1 Complex from Thermochromatium tepidum. Biochemistry 2016; 55:6495-6504. [PMID: 27933779 DOI: 10.1021/acs.biochem.6b00742] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
While the majority of the core light-harvesting complexes (LH1) in purple photosynthetic bacteria exhibit a Qy absorption band in the range of 870-890 nm, LH1 from the thermophilic bacterium Thermochromatium tepidum displays the Qy band at 915 nm with an enhanced thermostability. These properties are regulated by Ca2+ ions. Substitution of the Ca2+ with other divalent metal ions results in a complex with the Qy band blue-shifted to 880-890 nm and a reduced thermostability. Following the recent publication of the structure of the Ca-bound LH1-reaction center (RC) complex [Niwa, S., et al. (2014) Nature 508, 228], we have determined the crystal structures of the Sr- and Ba-substituted LH1-RC complexes with the LH1 Qy band at 888 nm. Sixteen Sr2+ and Ba2+ ions are identified in the LH1 complexes. Both Sr2+ and Ba2+ are located at the same positions, and these are clearly different from, though close to, the Ca2+-binding sites. Conformational rearrangement induced by the substitution is limited to the metal-binding sites. Unlike the Ca-LH1-RC complex, only the α-polypeptides are involved in the Sr and Ba coordinations in LH1. The difference in the thermostability between these complexes can be attributed to the different patterns of the network formed by metal binding. The Sr- and Ba-LH1-RC complexes form a single-ring network by the LH1 α-polypeptides only, in contrast to the double-ring network composed of both α- and β-polypeptides in the Ca-LH1-RC complex. On the basis of the structural information, a combined effect of hydrogen bonding, structural integrity, and charge distribution is considered to influence the spectral properties of the core antenna complex.
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Affiliation(s)
- Long-Jiang Yu
- Faculty of Science, Ibaraki University , Mito 310-8512, Japan
| | | | - Yukihiro Kimura
- Department of Agrobioscience, Graduate School of Agriculture, Kobe University , Nada, Kobe 657-8501, Japan
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17
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Selenium single-wavelength anomalous diffraction de novo phasing using an X-ray-free electron laser. Nat Commun 2016; 7:13388. [PMID: 27811937 PMCID: PMC5097167 DOI: 10.1038/ncomms13388] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 09/28/2016] [Indexed: 01/08/2023] Open
Abstract
Structural information about biological macromolecules near the atomic scale provides important insight into the functions of these molecules. To date, X-ray crystallography has been the predominant method used for macromolecular structure determination. However, challenges exist when solving structures with X-rays, including the phase problem and radiation damage. X-ray-free electron lasers (X-ray FELs) have enabled collection of diffraction information before the onset of radiation damage, yet the majority of structures solved at X-ray FELs have been phased using external information via molecular replacement. De novo phasing at X-ray FELs has proven challenging due in part to per-pulse variations in intensity and wavelength. Here we report the solution of a selenobiotinyl-streptavidin structure using phases obtained by the anomalous diffraction of selenium measured at a single wavelength (Se-SAD) at the Linac Coherent Light Source. Our results demonstrate Se-SAD, routinely employed at synchrotrons for novel structure determination, is now possible at X-ray FELs. X-ray free electron lasers are increasingly available for use in macromolecular structure determination. Here, the authors describe the successful use of selenium single-wavelength anomalous diffraction data to calculate experimentally derived phases.
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18
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Zander U, Cianci M, Foos N, Silva CS, Mazzei L, Zubieta C, de Maria A, Nanao MH. Merging of synchrotron serial crystallographic data by a genetic algorithm. Acta Crystallogr D Struct Biol 2016; 72:1026-35. [PMID: 27599735 PMCID: PMC5013596 DOI: 10.1107/s2059798316012079] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 07/25/2016] [Indexed: 11/10/2022] Open
Abstract
Recent advances in macromolecular crystallography have made it practical to rapidly collect hundreds of sub-data sets consisting of small oscillations of incomplete data. This approach, generally referred to as serial crystallography, has many uses, including an increased effective dose per data set, the collection of data from crystals without harvesting (in situ data collection) and studies of dynamic events such as catalytic reactions. However, selecting which data sets from this type of experiment should be merged can be challenging and new methods are required. Here, it is shown that a genetic algorithm can be used for this purpose, and five case studies are presented in which the merging statistics are significantly improved compared with conventional merging of all data.
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Affiliation(s)
- Ulrich Zander
- Structural Biology Group, European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Michele Cianci
- European Molecular Biology Laboratory, Hamburg Outstation, Building 25a, c/o DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Nicolas Foos
- Structural Biology Group, European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Catarina S. Silva
- Laboratoire de Physiologie Cellulaire et Végétale, Universite Grenoble Alpes, CNRS, CEA, INRA, BIG, Grenoble, France
| | - Luca Mazzei
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Chloe Zubieta
- Laboratoire de Physiologie Cellulaire et Végétale, Universite Grenoble Alpes, CNRS, CEA, INRA, BIG, Grenoble, France
| | - Alejandro de Maria
- Structural Biology Group, European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Max H. Nanao
- Structural Biology Group, European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France
- EMBL Grenoble, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble CEDEX 9, France
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19
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He H, Fang H, Miller MD, Phillips GN, Su WP. Improving the efficiency of molecular replacement by utilizing a new iterative transform phasing algorithm. Acta Crystallogr A Found Adv 2016; 72:539-47. [PMID: 27580202 PMCID: PMC5006650 DOI: 10.1107/s2053273316010731] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 07/02/2016] [Indexed: 01/09/2023] Open
Abstract
An iterative transform method proposed previously for direct phasing of high-solvent-content protein crystals is employed for enhancing the molecular-replacement (MR) algorithm in protein crystallography. Target structures that are resistant to conventional MR due to insufficient similarity between the template and target structures might be tractable with this modified phasing method. Trial calculations involving three different structures are described to test and illustrate the methodology. The relationship of the approach to PHENIX Phaser-MR and MR-Rosetta is discussed.
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Affiliation(s)
- Hongxing He
- Department of Physics and Texas Center for Superconductivity, University of Houston, Houston, Texas 77204, USA
| | - Hengrui Fang
- Department of Physics and Texas Center for Superconductivity, University of Houston, Houston, Texas 77204, USA
| | | | - George N. Phillips
- Department of BioSciences, Rice University, Houston, Texas 77005, USA
- Department of Chemistry, Rice University, Houston, Texas 77005, USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Wu-Pei Su
- Department of Physics and Texas Center for Superconductivity, University of Houston, Houston, Texas 77204, USA
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20
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Nass K, Meinhart A, Barends TRM, Foucar L, Gorel A, Aquila A, Botha S, Doak RB, Koglin J, Liang M, Shoeman RL, Williams G, Boutet S, Schlichting I. Protein structure determination by single-wavelength anomalous diffraction phasing of X-ray free-electron laser data. IUCRJ 2016; 3:180-91. [PMID: 27158504 PMCID: PMC4856140 DOI: 10.1107/s2052252516002980] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 02/18/2016] [Indexed: 05/23/2023]
Abstract
Serial femtosecond crystallography (SFX) at X-ray free-electron lasers (XFELs) offers unprecedented possibilities for macromolecular structure determination of systems that are prone to radiation damage. However, phasing XFEL data de novo is complicated by the inherent inaccuracy of SFX data, and only a few successful examples, mostly based on exceedingly strong anomalous or isomorphous difference signals, have been reported. Here, it is shown that SFX data from thaumatin microcrystals can be successfully phased using only the weak anomalous scattering from the endogenous S atoms. Moreover, a step-by-step investigation is presented of the particular problems of SAD phasing of SFX data, analysing data from a derivative with a strong anomalous signal as well as the weak signal from endogenous S atoms.
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Affiliation(s)
- Karol Nass
- Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - Anton Meinhart
- Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - Thomas R. M. Barends
- Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - Lutz Foucar
- Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - Alexander Gorel
- Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - Andrew Aquila
- European XFEL GmbH, Albert-Einstein-Ring 19, 22761 Hamburg, Germany
| | - Sabine Botha
- Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - R. Bruce Doak
- Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - Jason Koglin
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Mengning Liang
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Robert L. Shoeman
- Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - Garth Williams
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Sebastien Boutet
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Ilme Schlichting
- Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany
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21
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Rose JP, Wang BC. SAD phasing: History, current impact and future opportunities. Arch Biochem Biophys 2016; 602:80-94. [PMID: 27036852 DOI: 10.1016/j.abb.2016.03.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 03/17/2016] [Accepted: 03/19/2016] [Indexed: 01/17/2023]
Abstract
Single wavelength anomalous diffraction (SAD) can trace its beginnings to the early 1950s. Researchers at the time recognized that SAD offers some unique features that might be advantageous for crystallographic phasing, despite the fact that at that time recording accurate SAD data was problematic. In this review we will follow the trail from those early days, highlighting key advances in the field and interpreting them in terms on how they stimulated continued phasing development that produced the theoretical foundation for the routine macromolecular structure determination by SAD today. The technological advances over the past three decades in both hardware and software, which played a significant role in making SAD phasing a 'first choice method', will also be described.
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Affiliation(s)
- John P Rose
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA.
| | - Bi-Cheng Wang
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA.
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22
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Olieric V, Weinert T, Finke AD, Anders C, Li D, Olieric N, Borca CN, Steinmetz MO, Caffrey M, Jinek M, Wang M. Data-collection strategy for challenging native SAD phasing. Acta Crystallogr D Struct Biol 2016; 72:421-9. [PMID: 26960129 PMCID: PMC4784673 DOI: 10.1107/s2059798315024110] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 12/15/2015] [Indexed: 11/19/2022] Open
Abstract
Recent improvements in data-collection strategies have pushed the limits of native SAD (single-wavelength anomalous diffraction) phasing, a method that uses the weak anomalous signal of light elements naturally present in macromolecules. These involve the merging of multiple data sets from either multiple crystals or from a single crystal collected in multiple orientations at a low X-ray dose. Both approaches yield data of high multiplicity while minimizing radiation damage and systematic error, thus ensuring accurate measurements of the anomalous differences. Here, the combined use of these two strategies is described to solve cases of native SAD phasing that were particular challenges: the integral membrane diacylglycerol kinase (DgkA) with a low Bijvoet ratio of 1% and the large 200 kDa complex of the CRISPR-associated endonuclease (Cas9) bound to guide RNA and target DNA crystallized in the low-symmetry space group C2. The optimal native SAD data-collection strategy based on systematic measurements performed on the 266 kDa multiprotein/multiligand tubulin complex is discussed.
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Affiliation(s)
- Vincent Olieric
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - Tobias Weinert
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - Aaron D. Finke
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - Carolin Anders
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Dianfan Li
- Membrane Structural and Functional Group, Schools of Medicine and Biochemistry and Immunology, Trinity College, Dublin, Ireland
| | - Natacha Olieric
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - Camelia N. Borca
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - Michel O. Steinmetz
- Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institut, Villigen PSI, Switzerland
| | - Martin Caffrey
- Membrane Structural and Functional Group, Schools of Medicine and Biochemistry and Immunology, Trinity College, Dublin, Ireland
| | - Martin Jinek
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Meitian Wang
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, Switzerland
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23
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Read RJ, McCoy AJ. A log-likelihood-gain intensity target for crystallographic phasing that accounts for experimental error. Acta Crystallogr D Struct Biol 2016; 72:375-87. [PMID: 26960124 PMCID: PMC4784668 DOI: 10.1107/s2059798315013236] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 07/09/2015] [Indexed: 11/10/2022] Open
Abstract
The crystallographic diffraction experiment measures Bragg intensities; crystallographic electron-density maps and other crystallographic calculations in phasing require structure-factor amplitudes. If data were measured with no errors, the structure-factor amplitudes would be trivially proportional to the square roots of the intensities. When the experimental errors are large, and especially when random errors yield negative net intensities, the conversion of intensities and their error estimates into amplitudes and associated error estimates becomes nontrivial. Although this problem has been addressed intermittently in the history of crystallographic phasing, current approaches to accounting for experimental errors in macromolecular crystallography have numerous significant defects. These have been addressed with the formulation of LLGI, a log-likelihood-gain function in terms of the Bragg intensities and their associated experimental error estimates. LLGI has the correct asymptotic behaviour for data with large experimental error, appropriately downweighting these reflections without introducing bias. LLGI abrogates the need for the conversion of intensity data to amplitudes, which is usually performed with the French and Wilson method [French & Wilson (1978), Acta Cryst. A35, 517-525], wherever likelihood target functions are required. It has general applicability for a wide variety of algorithms in macromolecular crystallography, including scaling, characterizing anisotropy and translational noncrystallographic symmetry, detecting outliers, experimental phasing, molecular replacement and refinement. Because it is impossible to reliably recover the original intensity data from amplitudes, it is suggested that crystallographers should always deposit the intensity data in the Protein Data Bank.
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Affiliation(s)
- Randy J. Read
- Department of Haematology, University of Cambridge, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, England
| | - Airlie J. McCoy
- Department of Haematology, University of Cambridge, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, England
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24
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Pedersen BP, Gourdon P, Liu X, Karlsen JL, Nissen P. Initiating heavy-atom-based phasing by multi-dimensional molecular replacement. Acta Crystallogr D Struct Biol 2016; 72:440-5. [PMID: 26960131 PMCID: PMC4784675 DOI: 10.1107/s2059798315022482] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 11/24/2015] [Indexed: 11/29/2022] Open
Abstract
To obtain an electron-density map from a macromolecular crystal the phase problem needs to be solved, which often involves the use of heavy-atom derivative crystals and concomitant heavy-atom substructure determination. This is typically performed by dual-space methods, direct methods or Patterson-based approaches, which however may fail when only poorly diffracting derivative crystals are available. This is often the case for, for example, membrane proteins. Here, an approach for heavy-atom site identification based on a molecular-replacement parameter matrix (MRPM) is presented. It involves an n-dimensional search to test a wide spectrum of molecular-replacement parameters, such as different data sets and search models with different conformations. Results are scored by the ability to identify heavy-atom positions from anomalous difference Fourier maps. The strategy was successfully applied in the determination of a membrane-protein structure, the copper-transporting P-type ATPase CopA, when other methods had failed to determine the heavy-atom substructure. MRPM is well suited to proteins undergoing large conformational changes where multiple search models should be considered, and it enables the identification of weak but correct molecular-replacement solutions with maximum contrast to prime experimental phasing efforts.
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Affiliation(s)
- Bjørn Panyella Pedersen
- Centre for Membrane Pumps in Cells and Disease, Danish National Research Foundation, Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus, Denmark
| | - Pontus Gourdon
- Centre for Membrane Pumps in Cells and Disease, Danish National Research Foundation, Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus, Denmark
| | - Xiangyu Liu
- Centre for Membrane Pumps in Cells and Disease, Danish National Research Foundation, Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus, Denmark
| | - Jesper Lykkegaard Karlsen
- Centre for Membrane Pumps in Cells and Disease, Danish National Research Foundation, Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus, Denmark
| | - Poul Nissen
- Centre for Membrane Pumps in Cells and Disease, Danish National Research Foundation, Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus, Denmark
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25
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Terwilliger TC, Bunkóczi G, Hung LW, Zwart PH, Smith JL, Akey DL, Adams PD. Can I solve my structure by SAD phasing? Anomalous signal in SAD phasing. Acta Crystallogr D Struct Biol 2016; 72:346-58. [PMID: 26960122 PMCID: PMC4784666 DOI: 10.1107/s2059798315019269] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 10/12/2015] [Indexed: 12/19/2022] Open
Abstract
A key challenge in the SAD phasing method is solving a structure when the anomalous signal-to-noise ratio is low. A simple theoretical framework for describing measurements of anomalous differences and the resulting useful anomalous correlation and anomalous signal in a SAD experiment is presented. Here, the useful anomalous correlation is defined as the correlation of anomalous differences with ideal anomalous differences from the anomalous substructure. The useful anomalous correlation reflects the accuracy of the data and the absence of minor sites. The useful anomalous correlation also reflects the information available for estimating crystallographic phases once the substructure has been determined. In contrast, the anomalous signal (the peak height in a model-phased anomalous difference Fourier at the coordinates of atoms in the anomalous substructure) reflects the information available about each site in the substructure and is related to the ability to find the substructure. A theoretical analysis shows that the expected value of the anomalous signal is the product of the useful anomalous correlation, the square root of the ratio of the number of unique reflections in the data set to the number of sites in the substructure, and a function that decreases with increasing values of the atomic displacement factor for the atoms in the substructure. This means that the ability to find the substructure in a SAD experiment is increased by high data quality and by a high ratio of reflections to sites in the substructure, and is decreased by high atomic displacement factors for the substructure.
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Affiliation(s)
- Thomas C. Terwilliger
- Bioscience Division, Los Alamos National Laboratory, Mail Stop M888, Los Alamos, NM 87545, USA
| | - Gábor Bunkóczi
- Department of Haematology, University of Cambridge, Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Cambridge CB2 0XY, England
| | - Li-Wei Hung
- Physics Division, Los Alamos National Laboratory, Mail Stop D454, Los Alamos, NM 87545, USA
| | - Peter H. Zwart
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Janet L. Smith
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - David L. Akey
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Paul D. Adams
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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Terwilliger TC, Bunkóczi G, Hung LW, Zwart PH, Smith JL, Akey DL, Adams PD. Can I solve my structure by SAD phasing? Planning an experiment, scaling data and evaluating the useful anomalous correlation and anomalous signal. Acta Crystallogr D Struct Biol 2016; 72:359-74. [PMID: 26960123 PMCID: PMC4784667 DOI: 10.1107/s2059798315019403] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 10/13/2015] [Indexed: 01/15/2023] Open
Abstract
A key challenge in the SAD phasing method is solving a structure when the anomalous signal-to-noise ratio is low. Here, algorithms and tools for evaluating and optimizing the useful anomalous correlation and the anomalous signal in a SAD experiment are described. A simple theoretical framework [Terwilliger et al. (2016), Acta Cryst. D72, 346-358] is used to develop methods for planning a SAD experiment, scaling SAD data sets and estimating the useful anomalous correlation and anomalous signal in a SAD data set. The phenix.plan_sad_experiment tool uses a database of solved and unsolved SAD data sets and the expected characteristics of a SAD data set to estimate the probability that the anomalous substructure will be found in the SAD experiment and the expected map quality that would be obtained if the substructure were found. The phenix.scale_and_merge tool scales unmerged SAD data from one or more crystals using local scaling and optimizes the anomalous signal by identifying the systematic differences among data sets, and the phenix.anomalous_signal tool estimates the useful anomalous correlation and anomalous signal after collecting SAD data and estimates the probability that the data set can be solved and the likely figure of merit of phasing.
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Affiliation(s)
- Thomas C. Terwilliger
- Bioscience Division, Los Alamos National Laboratory, Mail Stop M888, Los Alamos, NM 87545, USA
| | - Gábor Bunkóczi
- Department of Haematology, University of Cambridge, Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Cambridge CB2 0XY, England
| | - Li-Wei Hung
- Physics Division, Los Alamos National Laboratory, Mail Stop D454, Los Alamos, NM 87545, USA
| | - Peter H. Zwart
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Janet L. Smith
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - David L. Akey
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Paul D. Adams
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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27
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Crystallographic phasing from weak anomalous signals. Curr Opin Struct Biol 2015; 34:99-107. [PMID: 26432413 DOI: 10.1016/j.sbi.2015.08.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 08/03/2015] [Accepted: 08/06/2015] [Indexed: 11/22/2022]
Abstract
The exploitation of anomalous signals for biological structural solution is maturing. Single-wavelength anomalous diffraction (SAD) is dominant in de novo structure analysis. Nevertheless, for challenging structures where the resolution is low (dmin≥3.5Å) or where only lighter atoms (Z≤20) are present, as for native macromolecules, solved SAD structures are still scarce. With the recent rapid development in crystal handling, beamline instrumentation, optimization of data collection strategies, use of multiple crystals and structure determination technologies, the weak anomalous diffraction signals are now robustly measured and should be used for routine SAD structure determination. The review covers these recent advances on weak anomalous signals measurement, analysis and utilization.
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28
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Rose JP, Wang BC, Weiss MS. Native SAD is maturing. IUCRJ 2015; 2:431-40. [PMID: 26175902 PMCID: PMC4491315 DOI: 10.1107/s2052252515008337] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 04/28/2015] [Indexed: 05/20/2023]
Abstract
Native SAD phasing uses the anomalous scattering signal of light atoms in the crystalline, native samples of macromolecules collected from single-wavelength X-ray diffraction experiments. These atoms include sodium, magnesium, phosphorus, sulfur, chlorine, potassium and calcium. Native SAD phasing is challenging and is critically dependent on the collection of accurate data. Over the past five years, advances in diffraction hardware, crystallographic software, data-collection methods and strategies, and the use of data statistics have been witnessed which allow 'highly accurate data' to be routinely collected. Today, native SAD sits on the verge of becoming a 'first-choice' method for both de novo and molecular-replacement structure determination. This article will focus on advances that have caught the attention of the community over the past five years. It will also highlight both de novo native SAD structures and recent structures that were key to methods development.
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Affiliation(s)
- John P. Rose
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Bi-Cheng Wang
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Manfred S. Weiss
- Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
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