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Chiasson S, Smith T, Bello L, Chandrika NT, Green KD, Garneau-Tsodikova S, Thompson MK. Small molecule inhibitors of the fosfomycin resistance enzyme FosM from Mycobacterium abscessus. Biochim Biophys Acta Gen Subj 2023; 1867:130444. [PMID: 37579984 PMCID: PMC10727124 DOI: 10.1016/j.bbagen.2023.130444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 08/09/2023] [Accepted: 08/10/2023] [Indexed: 08/16/2023]
Abstract
Fosfomycin is a safe broad-spectrum antibiotic that has not achieved widespread use because of the emergence of fosfomycin-modifying enzymes. Inhibition of fosfomycin-modifying enzymes could be used to help combat pathogens like Mycobacterium abscessus. Our previous work identified several inhibitors for the enzyme FosB from Staphylococcus aureus. We have tested those same compounds for inhibition of FosM, the fosfomycin-modifying enzyme from M. abscessus. The work described here will be used as the basis for more detailed studies into the inhibition of FosM.
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Affiliation(s)
- Skye Chiasson
- Department of Chemistry & Biochemistry, The University of Alabama, 250 Hackberry Lane, Tuscaloosa, AL 35487, United States of America
| | - Tatum Smith
- Department of Chemistry & Biochemistry, The University of Alabama, 250 Hackberry Lane, Tuscaloosa, AL 35487, United States of America
| | - Landon Bello
- Department of Chemistry & Biochemistry, The University of Alabama, 250 Hackberry Lane, Tuscaloosa, AL 35487, United States of America
| | - Nishad Thamban Chandrika
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone St., Lexington, KY 40536, United States of America
| | - Keith D Green
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone St., Lexington, KY 40536, United States of America
| | - Sylvie Garneau-Tsodikova
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone St., Lexington, KY 40536, United States of America
| | - Matthew K Thompson
- Department of Chemistry & Biochemistry, The University of Alabama, 250 Hackberry Lane, Tuscaloosa, AL 35487, United States of America.
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2
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Travis S, Green KD, Thamban Chandrika N, Pang AH, Frantom PA, Tsodikov OV, Garneau-Tsodikova S, Thompson MK. Identification and analysis of small molecule inhibitors of FosB from Staphylococcus aureus. RSC Med Chem 2023; 14:947-956. [PMID: 37252104 PMCID: PMC10211316 DOI: 10.1039/d3md00113j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 04/19/2023] [Indexed: 05/31/2023] Open
Abstract
Antimicrobial resistance (AMR) poses a significant threat to human health around the world. Though bacterial pathogens can develop resistance through a variety of mechanisms, one of the most prevalent is the production of antibiotic-modifying enzymes like FosB, a Mn2+-dependent l-cysteine or bacillithiol (BSH) transferase that inactivates the antibiotic fosfomycin. FosB enzymes are found in pathogens such as Staphylococcus aureus, one of the leading pathogens in deaths associated with AMR. fosB gene knockout experiments establish FosB as an attractive drug target, showing that the minimum inhibitory concentration (MIC) of fosfomycin is greatly reduced upon removal of the enzyme. Herein, we have identified eight potential inhibitors of the FosB enzyme from S. aureus by applying high-throughput in silico screening of the ZINC15 database with structural similarity to phosphonoformate, a known FosB inhibitor. In addition, we have obtained crystal structures of FosB complexes to each compound. Furthermore, we have kinetically characterized the compounds with respect to inhibition of FosB. Finally, we have performed synergy assays to determine if any of the new compounds lower the MIC of fosfomycin in S. aureus. Our results will inform future studies on inhibitor design for the FosB enzymes.
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Affiliation(s)
- Skye Travis
- Department of Chemistry & Biochemistry, The University of Alabama Box 870336, 250 Hackberry Lane Tuscaloosa AL 35487 USA +(205) 348 8439
| | - Keith D Green
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky 789 South Limestone St. Lexington KY 40536 USA
| | - Nishad Thamban Chandrika
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky 789 South Limestone St. Lexington KY 40536 USA
| | - Allan H Pang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky 789 South Limestone St. Lexington KY 40536 USA
| | - Patrick A Frantom
- Department of Chemistry & Biochemistry, The University of Alabama Box 870336, 250 Hackberry Lane Tuscaloosa AL 35487 USA +(205) 348 8439
| | - Oleg V Tsodikov
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky 789 South Limestone St. Lexington KY 40536 USA
| | - Sylvie Garneau-Tsodikova
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky 789 South Limestone St. Lexington KY 40536 USA
| | - Matthew K Thompson
- Department of Chemistry & Biochemistry, The University of Alabama Box 870336, 250 Hackberry Lane Tuscaloosa AL 35487 USA +(205) 348 8439
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Travis S, Green KD, Gilbert NC, Tsodikov OV, Garneau-Tsodikova S, Thompson MK. Inhibition of Fosfomycin Resistance Protein FosB from Gram-Positive Pathogens by Phosphonoformate. Biochemistry 2023; 62:109-117. [PMID: 36525630 DOI: 10.1021/acs.biochem.2c00566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The Gram-positive pathogen Staphylococcus aureus is a leading cause of antimicrobial resistance related deaths worldwide. Like many pathogens with multidrug-resistant strains, S. aureus contains enzymes that confer resistance through antibiotic modification(s). One such enzyme present in S. aureus is FosB, a Mn2+-dependent l-cysteine or bacillithiol (BSH) transferase that inactivates the antibiotic fosfomycin. fosB gene knockout experiments show that the minimum inhibitory concentration (MIC) of fosfomycin is significantly reduced when the FosB enzyme is not present. This suggests that inhibition of FosB could be an effective method to restore fosfomycin activity. We used high-throughput in silico-based screening to identify small-molecule analogues of fosfomycin that inhibited thiol transferase activity. Phosphonoformate (PPF) was a top hit from our approach. Herein, we have characterized PPF as a competitive inhibitor of FosB from S. aureus (FosBSa) and Bacillus cereus (FosBBc). In addition, we have determined a crystal structure of FosBBc with PPF bound in the active site. Our results will be useful for future structure-based development of FosB inhibitors that can be delivered in combination with fosfomycin in order to increase the efficacy of this antibiotic.
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Affiliation(s)
- Skye Travis
- Department of Chemistry & Biochemistry, The University of Alabama, 250 Hackberry Lane, Tuscaloosa, Alabama 35487, United States
| | - Keith D Green
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536, United States
| | - Nathaniel C Gilbert
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Oleg V Tsodikov
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536, United States
| | - Sylvie Garneau-Tsodikova
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, Kentucky 40536, United States
| | - Matthew K Thompson
- Department of Chemistry & Biochemistry, The University of Alabama, 250 Hackberry Lane, Tuscaloosa, Alabama 35487, United States
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Wang H, Huang SD, Yan L, Hu MY, Zhao J, Alp EE, Yoda Y, Petersen CM, Thompson MK. Europium-151 and iron-57 nuclear resonant vibrational spectroscopy of naturally abundant KEu(III)Fe(II)(CN) 6 and Eu(III)Fe(III)(CN) 6 complexes. Dalton Trans 2022; 51:17753-17761. [PMID: 36346270 PMCID: PMC9933908 DOI: 10.1039/d2dt02600g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have performed and analyzed the first combined 151Eu and 57Fe nuclear resonant vibrational spectroscopy (NRVS) for naturally abundant KEu(III)[Fe(II)(CN)6] and Eu(III)[Fe(III)(CN)6] complexes. Comparison of the observed 151Eu vs.57Fe NRVS spectroscopic features confirms that Eu(III) in both KEu(III)[Fe(II)(CN)6] and Eu(III)[Fe(III)(CN)6] occupies a position outside the [Fe(CN)6] core and coordinates to the N atoms of the CN- ions, whereas Fe(III) or Fe(II) occupies the site inside the [Fe(CN)6]4- core and coordinates to the C atoms of the CN- ions. In addition to the spectroscopic interest, the results from this study provide invaluable insights for the design and evaluation of the nanoparticles of such complexes as potential cellular contrast agents for their use in magnetic resonance imaging. The combined 151Eu and 57Fe NRVS measurements are also among the first few explorations of bi-isotopic NRVS experiments.
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Affiliation(s)
| | - Songping D Huang
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA.
| | - Lifen Yan
- SETI Institute, Mountain View, CA 94043, USA.
| | - Michael Y Hu
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Jiyong Zhao
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Ercan E Alp
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Yoshitaka Yoda
- Precision Spectroscopy Division, SPring-8/JASRI, Sayo, Hyogo 679-5198, Japan
| | - Courtney M Petersen
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Matthew K Thompson
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, AL 35487, USA
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Wiltsie V, Travis S, Shay MR, Simmons Z, Frantom P, Thompson MK. Structural and functional characterization of fosfomycin resistance conferred by FosB from Enterococcus faecium. Protein Sci 2022; 31:580-590. [PMID: 34882867 PMCID: PMC8862413 DOI: 10.1002/pro.4253] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 12/02/2021] [Accepted: 12/03/2021] [Indexed: 11/10/2022]
Abstract
The Gram-positive pathogen Enterococcus faecium is one of the leading causes of hospital-acquired vancomycin resistant enterococci (VRE) infections. E. faecium has extensive multidrug resistance and accounts for more than two million infections in the United States each year. FosB is a fosfomycin resistance enzyme found in Gram-positive pathogens like E. faecium. Typically, the FosB enzymes are Mn2+ -dependent bacillithiol (BSH) transferases that inactivate fosfomycin through nucleophilic addition of the thiol to the antibiotic. However, our kinetic analysis of FosBEf shows that the enzyme does not utilize BSH as a thiol substrate, unlike the other well characterized FosB enzymes. Here we report that FosBEf is a Mn2+ -dependent L-cys transferase. In addition, we have determined the three-dimensional X-ray crystal structure of FosBEf in complex with fosfomycin at a resolution of 2.0 Å. A sequence similarity network (SSN) was generated for the FosB family to investigate the unexpected substrate selectivity. Three non-conserved residues were identified in the SSN that may contribute to the substrate selectivity differences in the family of enzymes. Our structural and functional characterization of FosBEf establishes the enzyme as a potential target and may prove useful for future structure-based development of FosB inhibitors to increase the efficacy of fosfomycin.
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Affiliation(s)
- Vanessa Wiltsie
- Department of Chemistry & BiochemistryThe University of AlabamaTuscaloosaAlabamaUSA
| | - Skye Travis
- Department of Chemistry & BiochemistryThe University of AlabamaTuscaloosaAlabamaUSA
| | - Madeline R. Shay
- Department of Chemistry & BiochemistryThe University of AlabamaTuscaloosaAlabamaUSA
| | - Zachary Simmons
- Department of Chemistry & BiochemistryThe University of AlabamaTuscaloosaAlabamaUSA
| | - Patrick Frantom
- Department of Chemistry & BiochemistryThe University of AlabamaTuscaloosaAlabamaUSA
| | - Matthew K. Thompson
- Department of Chemistry & BiochemistryThe University of AlabamaTuscaloosaAlabamaUSA
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Petersen CM, Wang H, George SJ, Yoda Y, Nagasawa N, Matsuura H, Cramer SP, Thompson MK. Exploring the basis for substrate-dependent control of [4Fe4S] redox properties in human DNA primase. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.1026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Oladipupo O, Brown SR, Lamb RW, Gray JL, Cameron CG, DeRegnaucourt AR, Ward NA, Hall JF, Xu Y, Petersen CM, Qu F, Shrestha AB, Thompson MK, Bonizzoni M, Webster CE, McFarland SA, Kim Y, Papish ET. Light-responsive and Protic Ruthenium Compounds Bearing Bathophenanthroline and Dihydroxybipyridine Ligands Achieve Nanomolar Toxicity towards Breast Cancer Cells. Photochem Photobiol 2022; 98:102-116. [PMID: 34411308 PMCID: PMC8810589 DOI: 10.1111/php.13508] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 08/16/2021] [Indexed: 01/03/2023]
Abstract
We report new ruthenium complexes bearing the lipophilic bathophenanthroline (BPhen) ligand and dihydroxybipyridine (dhbp) ligands which differ in the placement of the OH groups ([(BPhen)2 Ru(n,n'-dhbp)]Cl2 with n = 6 and 4 in 1A and 2A , respectively). Full characterization data are reported for 1A and 2A and single crystal X-ray diffraction for 1A . Both 1A and 2A are diprotic acids. We have studied 1A , 1B , 2A , and 2B (B = deprotonated forms) by UV-vis spectroscopy and 1 photodissociates, but 2 is light stable. Luminescence studies reveal that the basic forms have lower energy 3 MLCT states relative to the acidic forms. Complexes 1A and 2A produce singlet oxygen with quantum yields of 0.05 and 0.68, respectively, in acetonitrile. Complexes 1 and 2 are both photocytotoxic toward breast cancer cells, with complex 2 showing EC50 light values as low as 0.50 μM with PI values as high as >200 vs. MCF7. Computational studies were used to predict the energies of the 3 MLCT and 3 MC states. An inaccessible 3 MC state for 2B suggests a rationale for why photodissociation does not occur with the 4,4'-dhbp ligand. Low dark toxicity combined with an accessible 3 MLCT state for 1 O2 generation explains the excellent photocytotoxicity of 2.
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Affiliation(s)
- Olaitan Oladipupo
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Spenser R. Brown
- Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Robert W. Lamb
- Department of Chemistry, Mississippi State University, Mississippi State, MS 39762, USA.,Oak Ridge Institute for Science and Education, Oak Ridge, TN 37830, USA
| | - Jessica L. Gray
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Colin G. Cameron
- Department of Chemistry and Biochemistry, University of Texas Arlington, Arlington, TX 76019, USA
| | - Alexa R. DeRegnaucourt
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Nicholas A. Ward
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - James Fletcher Hall
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Yifei Xu
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Courtney M. Petersen
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Fengrui Qu
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Ambar B. Shrestha
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Matthew K. Thompson
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Marco Bonizzoni
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, AL 35487, USA
| | - Charles Edwin Webster
- Department of Chemistry, Mississippi State University, Mississippi State, MS 39762, USA.,Corresponding Authors’: (Charles Edwin Webster), (Sherri A. McFarland), (Yonghyun Kim), (Elizabeth T. Papish)
| | - Sherri A. McFarland
- Department of Chemistry and Biochemistry, University of Texas Arlington, Arlington, TX 76019, USA.,Corresponding Authors’: (Charles Edwin Webster), (Sherri A. McFarland), (Yonghyun Kim), (Elizabeth T. Papish)
| | - Yonghyun Kim
- Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, AL 35487, USA.,Corresponding Authors’: (Charles Edwin Webster), (Sherri A. McFarland), (Yonghyun Kim), (Elizabeth T. Papish)
| | - Elizabeth T. Papish
- Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, AL 35487, USA.,Corresponding Authors’: (Charles Edwin Webster), (Sherri A. McFarland), (Yonghyun Kim), (Elizabeth T. Papish)
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Thompson MK, Gale D, Brenton JD. Circulating tumour DNA for clinicians: current and future clinical applications. Clin Radiol 2021; 76:737-747. [PMID: 34389159 DOI: 10.1016/j.crad.2021.07.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 07/20/2021] [Indexed: 12/12/2022]
Abstract
This review introduces clinicians to the basic concepts of the biology of circulating tumour DNA (ctDNA), which is required to understand clinical use of ctDNA technology. We provide an overview of how new technology has improved the sensitivity of ctDNA detection over the last decade and the available techniques for ctDNA analysis including whole-genome sequencing (WGS), targeted cancer-associated gene panels, and methylation analysis. We discuss the most recent evidence from clinical trials for ctDNA in patient care including precision treatment of advanced cancers, disease monitoring, improving adjuvant treatment, and screening for early detection of cancer. Finally, we outline how ctDNA is likely to directly impact radiologists, and identify further research required for ctDNA to progress into routine clinical application.
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Affiliation(s)
- M K Thompson
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, CB2 0RE, UK; Department of Oncology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, CB2 0QQ, UK; Cancer Research UK Cambridge Centre, University of Cambridge, Cambridge, CB2 0RE, UK.
| | - D Gale
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, CB2 0RE, UK; Cancer Research UK Cambridge Centre, University of Cambridge, Cambridge, CB2 0RE, UK
| | - J D Brenton
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, CB2 0RE, UK; Department of Oncology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, CB2 0QQ, UK; Cancer Research UK Cambridge Centre, University of Cambridge, Cambridge, CB2 0RE, UK
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Thompson MK, Shay MR, de Serrano V, Dumarieh R, Ghiladi RA, Franzen S. A new inhibition mechanism in the multifunctional catalytic hemoglobin dehaloperoxidase as revealed by the DHP A(V59W) mutant: A spectroscopic and crystallographic study. J PORPHYR PHTHALOCYA 2021. [DOI: 10.1142/s1088424621500826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
As multifunctional catalytic hemoglobins, dehaloperoxidase isoenzymes A and B (DHP A and B) are among the most versatile hemoproteins in terms of activities displayed. The ability of DHP to bind over twenty different substrates in the distal pocket might appear to resemble the promiscuousness of monooxygenase enzymes, yet there are identifiable substrate-specific interactions that can steer the type of oxidation (O-atom vs. electron transfer) that occurs inside the DHP distal pocket. Here, we have investigated the DHP A(V59W) mutant in order to probe the limits of conformational flexibility in the distal pocket as it relates to the genesis of this substrate-dependent activity differentiation. The X-ray crystal structure of the metaquo DHP A(V59W) mutant (PDB 3K3U) and the V59W mutant in complex with fluoride [denoted as DHP A(V59W-F)] (PDB 7MNH) show significant mobility of the tryptophan in the distal pocket, with two parallel conformations having W59-N[Formula: see text] H-bonded to a heme-bound ligand (H2O or F[Formula: see text], and another conformation [observed only in DHP A(V59W-F)] that brings W59 sufficiently close to the heme as to preclude axial ligand binding. UV-vis and resonance Raman spectroscopic studies show that DHP A(V59W) is 5-coordinate high spin (5cHS) at pH 5 and 6-coordinate high spin (6cHS) at pH 7, whereas DHP A(V59W-F) is 6cHS from pH 5 to 7. Enzyme assays confirm robust peroxidase activity at pH 5, but complete loss of activity at pH 7. We find no evidence that tryptophan plays a role in the oxidation mechanism ([Formula: see text]. radical formation). Instead, the data reveal a new mechanism of DHP inhibition, namely a shift towards a non-reactive form by OH[Formula: see text] ligation to the heme-Fe that is strongly stabilized (presumably through H-bonding interactions) by the presence of W59 in the distal cavity.
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Affiliation(s)
- Matthew K. Thompson
- Department of Chemistry & Biochemistry, University of Alabama, 250 Hackberry Lane, Tuscaloosa, AL 35487, USA
| | - Madeline R. Shay
- Department of Chemistry & Biochemistry, University of Alabama, 250 Hackberry Lane, Tuscaloosa, AL 35487, USA
| | - Vesna de Serrano
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA
| | - Rania Dumarieh
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA
| | - Reza A. Ghiladi
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA
| | - Stefan Franzen
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA
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Petersen CM, Edwards KC, Gilbert NC, Vincent JB, Thompson MK. X-ray structure of chromium(III)-containing transferrin: First structure of a physiological Cr(III)-binding protein. J Inorg Biochem 2020; 210:111101. [PMID: 32650146 DOI: 10.1016/j.jinorgbio.2020.111101] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 04/28/2020] [Accepted: 05/02/2020] [Indexed: 02/05/2023]
Abstract
Transferrin, the Fe(III) transport protein in mammalian blood, has been suggested to also serve as a Cr(III) transporter and as part of a Cr(III) detoxification system; however, the structure of the metal-binding sites has never been fully elucidated with bound Cr(III). Chromium(III)-transferrin was crystallized in the presence of the synergistic anion malonate. In the crystals, the protein exists with a closed C-terminal lobe containing a Cr(III) ion and an open, unoccupied N-terminal lobe. The overall structure and the metal ion environments are extremely similar to those of Fe(III)- and Ti(IV)-containing transferrin crystallized under comparable conditions. The octahedral coordination about the Cr(III) is comprised of four ligands provided by the protein (two tyrosine residues, a histidine residue, and an aspartate residue) and a chelating malonate anion. This represents the first crystal structure of a Cr(III)-containing protein that binds Cr(III) as part of its physiological function.
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Affiliation(s)
- Courtney M Petersen
- Department of Chemistry & Biochemistry, The University of Alabama, 250 Hackberry Lane, Tuscaloosa, AL 35487-0336, USA
| | - Kyle C Edwards
- Department of Chemistry & Biochemistry, The University of Alabama, 250 Hackberry Lane, Tuscaloosa, AL 35487-0336, USA
| | - Nathaniel C Gilbert
- Center for Advanced Microstructure & Devices, Louisiana State University, 6980 Jefferson Highway, Baton Rouge, LA 70806, USA
| | - John B Vincent
- Department of Chemistry & Biochemistry, The University of Alabama, 250 Hackberry Lane, Tuscaloosa, AL 35487-0336, USA
| | - Matthew K Thompson
- Department of Chemistry & Biochemistry, The University of Alabama, 250 Hackberry Lane, Tuscaloosa, AL 35487-0336, USA.
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Travis S, Shay MR, Manabe S, Gilbert NC, Frantom PA, Thompson MK. Characterization of the genomically encoded fosfomycin resistance enzyme from Mycobacterium abscessus. Medchemcomm 2019; 10:1948-1957. [PMID: 32952996 PMCID: PMC7478155 DOI: 10.1039/c9md00372j] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 09/17/2019] [Indexed: 01/03/2023]
Abstract
Mycobacterium abscessus belongs to a group of rapidly growing mycobacteria (RGM) and accounts for approximately 65-80% of lung disease caused by RGM. It is highly pathogenic and is considered the prominent Mycobacterium involved in pulmonary infection in patients with cystic fibrosis and chronic pulmonary disease (CPD). FosM is a putative 134 amino acid fosfomycin resistance enzyme from M. abscessus subsp. bolletii that shares approximately 30-55% sequence identity with other vicinal oxygen chelate (VOC) fosfomycin resistance enzymes and represents the first of its type found in any Mycobacterium species. Genes encoding VOC fosfomycin resistance enzymes have been found in both Gram-positive and Gram-negative pathogens. Given that FosA enzymes from Gram-negative bacteria have evolved optimum activity towards glutathione (GSH) and FosB enzymes from Gram-positive bacteria have evolved optimum activity towards bacillithiol (BSH), it was originally suggested that FosM might represent a fourth class of enzyme that has evolved to utilize mycothiol (MSH). However, a sequence similarity network (SSN) analysis identifies FosM as a member of the FosX subfamily, indicating that it may utilize water as a substrate. Here we have synthesized MSH and characterized FosM with respect to divalent metal ion activation and nucleophile selectivity. Our results indicate that FosM is a Mn2+-dependent FosX-type hydrase with no selectivity toward MSH or other thiols as analyzed by NMR and mass spectroscopy.
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Affiliation(s)
- Skye Travis
- Department of Chemistry & Biochemistry , The University of Alabama , 250 Hackberry Lane , Box 870336 , Tuscaloosa , AL 35487 , USA . ; Tel: +(205) 348 7020
| | - Madeline R Shay
- Department of Chemistry & Biochemistry , The University of Alabama , 250 Hackberry Lane , Box 870336 , Tuscaloosa , AL 35487 , USA . ; Tel: +(205) 348 7020
| | - Shino Manabe
- Synthetic Cellular Chemistry Laboratory , RIKEN , Hirosawa , Wako , Saitama 351-0198 , Japan
| | - Nathaniel C Gilbert
- Center for Advanced Microstructures and Devices , Louisiana State University , 6980 Jefferson Highway , Baton Rouge , Louisiana 70806 , USA
| | - Patrick A Frantom
- Department of Chemistry & Biochemistry , The University of Alabama , 250 Hackberry Lane , Box 870336 , Tuscaloosa , AL 35487 , USA . ; Tel: +(205) 348 7020
| | - Matthew K Thompson
- Department of Chemistry & Biochemistry , The University of Alabama , 250 Hackberry Lane , Box 870336 , Tuscaloosa , AL 35487 , USA . ; Tel: +(205) 348 7020
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Shay MR, Travis S, Thompson MK. Structural Characterization of FosM from Mycobacterium abscessus. Biophys J 2019. [DOI: 10.1016/j.bpj.2018.11.1813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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13
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Johnson CN, Potet F, Thompson MK, Kroncke BM, Glazer AM, Voehler MW, Knollmann BC, George AL, Chazin WJ. A Mechanism of Calmodulin Modulation of the Human Cardiac Sodium Channel. Structure 2018; 26:683-694.e3. [PMID: 29606593 DOI: 10.1016/j.str.2018.03.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 01/26/2018] [Accepted: 03/08/2018] [Indexed: 12/26/2022]
Abstract
The function of the human cardiac sodium channel (NaV1.5) is modulated by the Ca2+ sensor calmodulin (CaM), but the underlying mechanism(s) are controversial and poorly defined. CaM has been reported to bind in a Ca2+-dependent manner to two sites in the intracellular loop that is critical for inactivation of NaV1.5 (inactivation gate [IG]). The affinity of CaM for the complete IG was significantly stronger than that of fragments that lacked both complete binding sites. Structural analysis by nuclear magnetic resonance, crystallographic, and scattering approaches revealed that CaM simultaneously engages both IG sites using an extended configuration. Patch-clamp recordings for wild-type and mutant channels with an impaired CaM-IG interaction revealed CaM binding to the IG promotes recovery from inactivation while impeding the kinetics of inactivation. Models of full-length NaV1.5 suggest that CaM binding to the IG directly modulates channel function by destabilizing the inactivated state, which would promote resetting of the IG after channels close.
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Affiliation(s)
- Christopher N Johnson
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN 37240, USA; Department of Biochemistry, Vanderbilt University, Nashville, TN 37205, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA; Center for Arrhythmia Research and Therapeutics, Vanderbilt University, Nashville, TN 37240, USA.
| | - Franck Potet
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago IL 60611, USA
| | - Matthew K Thompson
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37205, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Brett M Kroncke
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN 37240, USA; Center for Arrhythmia Research and Therapeutics, Vanderbilt University, Nashville, TN 37240, USA
| | - Andrew M Glazer
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN 37240, USA; Center for Arrhythmia Research and Therapeutics, Vanderbilt University, Nashville, TN 37240, USA
| | - Markus W Voehler
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Bjorn C Knollmann
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN 37240, USA; Center for Arrhythmia Research and Therapeutics, Vanderbilt University, Nashville, TN 37240, USA
| | - Alfred L George
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago IL 60611, USA
| | - Walter J Chazin
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37205, USA; Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA.
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14
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O'Brien E, Holt ME, Thompson MK, Salay LE, Ehlinger AC, Chazin WJ, Barton JK. The [4Fe4S] cluster of human DNA primase functions as a redox switch using DNA charge transport. Science 2017; 355:355/6327/eaag1789. [PMID: 28232525 DOI: 10.1126/science.aag1789] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 01/23/2017] [Indexed: 01/05/2023]
Abstract
DNA charge transport chemistry offers a means of long-range, rapid redox signaling. We demonstrate that the [4Fe4S] cluster in human DNA primase can make use of this chemistry to coordinate the first steps of DNA synthesis. Using DNA electrochemistry, we found that a change in oxidation state of the [4Fe4S] cluster acts as a switch for DNA binding. Single-atom mutations that inhibit this charge transfer hinder primase initiation without affecting primase structure or polymerization. Generating a single base mismatch in the growing primer duplex, which attenuates DNA charge transport, inhibits primer truncation. Thus, redox signaling by [4Fe4S] clusters using DNA charge transport regulates primase binding to DNA and illustrates chemistry that may efficiently drive substrate handoff between polymerases during DNA replication.
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Affiliation(s)
- Elizabeth O'Brien
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Marilyn E Holt
- Departments of Biochemistry and Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
| | - Matthew K Thompson
- Departments of Biochemistry and Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
| | - Lauren E Salay
- Departments of Biochemistry and Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
| | - Aaron C Ehlinger
- Departments of Biochemistry and Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
| | - Walter J Chazin
- Departments of Biochemistry and Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA.
| | - Jacqueline K Barton
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
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15
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Abstract
Eicosanoids are inflammatory signaling lipids that are biosynthesized in response to cellular injury or threat. They were originally thought to be pro-inflammatory molecules, but members of at least one subclass, the lipoxins, are able to resolve inflammation. One step in lipoxin synthesis is the oxygenation of arachidonic acid by 15-lipoxygenase (15-LOX). 15-LOX contains two domains: a Ca2+ binding PLAT domain and a catalytic domain. 15-LOX is a soluble cytosolic protein until binding of Ca2+ to the PLAT domain promotes translocation to the membrane surface. The role of 15-LOX structural dynamics in this translocation has remained unclear. We investigated the dynamics of 15-LOX isoform B (15-LOX-2) upon binding of Ca2+ and ligands, as well as upon membrane association using hydrogen-deuterium exchange mass spectrometry (HDX-MS). We used HDX-MS to probe the solvent accessibility and backbone flexibility of 15-LOX-2, revealing significant differences in deuterium incorporation between the PLAT and catalytic domains, with the PLAT domain demonstrating higher flexibility. Comparison of HDX for 15-LOX-2 in the presence and absence of Ca2+ indicates there are few differences in structural dynamics. Furthermore, our HDX results involving nanodisc-associated 15-LOX-2 suggest that significant structural and dynamic changes in 15-LOX-2 are not required for membrane association. Our results also show that a substrate lipid binding to the active site in the catalytic domain does induce changes in incorporation of deuterium into the PLAT domain. Overall, our results challenge the previous hypothesis that Ca2+ binding induces major structural changes in the PLAT domain and support the hypothesis that is interdomain communication in 15-LOX-2.
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Affiliation(s)
- Kristin D Droege
- Department of Chemistry, Vanderbilt University , Nashville, Tennessee 37232, United States
| | - Mary E Keithly
- Department of Chemical and Physical Sciences, Missouri Southern State University , Joplin, Missouri 64801, United States
| | - Charles R Sanders
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University School of Medicine , Nashville, Tennessee 37240, United States
| | - Richard N Armstrong
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University School of Medicine , Nashville, Tennessee 37240, United States
| | - Matthew K Thompson
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University School of Medicine , Nashville, Tennessee 37240, United States
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16
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O'Brien E, Holt ME, Thompson MK, Salay LE, Ehlinger AC, Chazin WJ, Barton JK. Response to Comments on "The [4Fe4S] cluster of human DNA primase functions as a redox switch using DNA charge transport". Science 2017; 357:eaan2762. [PMID: 28729485 PMCID: PMC5935490 DOI: 10.1126/science.aan2762] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 06/13/2017] [Indexed: 11/02/2022]
Abstract
Baranovskiy et al and Pellegrini argue that, based on structural data, the path for charge transfer through the [4Fe4S] domain of primase is not feasible. Our manuscript presents electrochemical data directly showing charge transport through DNA to the [4Fe4S] cluster of a primase p58C construct and a reversible switch in the DNA-bound signal with oxidation/reduction, which is inhibited by mutation of three tyrosine residues. Although the dispositions of tyrosines differ in different constructs, all are within range for microsecond electron transfer.
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Affiliation(s)
- Elizabeth O'Brien
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Marilyn E Holt
- Departments of Biochemistry and Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
| | - Matthew K Thompson
- Departments of Biochemistry and Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
| | - Lauren E Salay
- Departments of Biochemistry and Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
| | - Aaron C Ehlinger
- Departments of Biochemistry and Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA
| | - Walter J Chazin
- Departments of Biochemistry and Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN 37235, USA.
| | - Jacqueline K Barton
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
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17
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Abstract
Multiprotein machines drive virtually all primary cellular processes. Modular multidomain proteins are widely distributed within these dynamic complexes because they provide the flexibility needed to remodel structure as well as rapidly assemble and disassemble components of the machinery. Understanding the functional dynamics of modular multidomain proteins is a major challenge confronting structural biology today because their structure is not fixed in time. Small-angle X-ray scattering (SAXS) and nuclear magnetic resonance (NMR) spectroscopy have proven particularly useful for the analysis of the structural dynamics of modular multidomain proteins because they provide highly complementary information for characterizing the architectural landscape accessible to these proteins. SAXS provides a global snapshot of all architectural space sampled by a molecule in solution. Furthermore, SAXS is sensitive to conformational changes, organization and oligomeric states of protein assemblies, and the existence of flexibility between globular domains in multiprotein complexes. The power of NMR to characterize dynamics provides uniquely complementary information to the global snapshot of the architectural ensemble provided by SAXS because it can directly measure domain motion. In particular, NMR parameters can be used to define the diffusion of domains within modular multidomain proteins, connecting the amplitude of interdomain motion to the architectural ensemble derived from SAXS. Our laboratory has been studying the roles of modular multidomain proteins involved in human DNA replication using SAXS and NMR. Here, we present the procedure for acquiring and analyzing SAXS and NMR data, using DNA primase and replication protein A as examples.
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Affiliation(s)
- Matthew K Thompson
- Departments of Biochemistry and Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN, United States
| | - Aaron C Ehlinger
- Departments of Biochemistry and Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN, United States
| | - Walter J Chazin
- Departments of Biochemistry and Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN, United States.
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Paquette AM, Harahap A, Laosombat V, Patnode JM, Satyagraha A, Sudoyo H, Thompson MK, Yusoff NM, Wilder JA. The evolutionary origins of Southeast Asian Ovalocytosis. Infect Genet Evol 2015; 34:153-9. [PMID: 26047685 DOI: 10.1016/j.meegid.2015.06.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 05/25/2015] [Accepted: 06/01/2015] [Indexed: 11/30/2022]
Abstract
Southeast Asian Ovalocytosis (SAO) is a common red blood cell disorder that is maintained as a balanced polymorphism in human populations. In individuals heterozygous for the SAO-causing mutation there are minimal detrimental effects and well-documented protection from severe malaria caused by Plasmodium vivax and Plasmodium falciparum; however, the SAO-causing mutation is fully lethal in utero when homozygous. The present-day high frequency of SAO in Island Southeast Asia indicates the trait is maintained by strong heterozygote advantage. Our study elucidates the evolutionary origin of SAO by characterizing DNA sequence variation in a 9.5 kilobase region surrounding the causal mutation in the SLC4A1 gene. We find substantial haplotype diversity among SAO chromosomes and estimate the age of the trait to be approximately 10,005 years (95% CI: 4930-23,200 years). This date is far older than any other human malaria-resistance trait examined previously in Southeast Asia, and considerably pre-dates the widespread adoption of agriculture associated with the spread of speakers of Austronesian languages some 4000 years ago. Using a genealogy-based method we find no evidence of historical positive selection acting on SAO (s=0.0, 95% CI: 0.0-0.03), in sharp contrast to the strong present-day selection coefficient (e.g., 0.09) estimated from the frequency of this recessively lethal trait. This discrepancy may be due to a recent increase in malaria-driven selection pressure following the spread of agriculture, with SAO targeted as a standing variant by positive selection in malarial populations.
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Affiliation(s)
- A M Paquette
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - A Harahap
- Eijkman Institute for Molecular Biology, Jakarta, Indonesia
| | - V Laosombat
- Division of Pediatric Hematology & Oncology, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkla 90110, Thailand
| | - J M Patnode
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - A Satyagraha
- Eijkman Institute for Molecular Biology, Jakarta, Indonesia
| | - H Sudoyo
- Eijkman Institute for Molecular Biology, Jakarta, Indonesia
| | - M K Thompson
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - N M Yusoff
- Advanced Medical and Dental Institute, Universiti Sains Malaysia, 13200 Kepala Batas, Pulau Pinang, Malaysia
| | - J A Wilder
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA.
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20
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21
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Thompson MK, Keithly ME, Goodman MC, Hammer ND, Cook PD, Jagessar KL, Harp J, Skaar EP, Armstrong RN. Structure and function of the genomically encoded fosfomycin resistance enzyme, FosB, from Staphylococcus aureus. Biochemistry 2014; 53:755-65. [PMID: 24447055 PMCID: PMC3985756 DOI: 10.1021/bi4015852] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
![]()
The
Gram-positive pathogen Staphylococcus aureus is a
leading cause of global morbidity and mortality. Like many
multi-drug-resistant organisms, S. aureus contains
antibiotic-modifying enzymes that facilitate resistance to a multitude
of antimicrobial compounds. FosB is a Mn2+-dependent fosfomycin-inactivating
enzyme found in S. aureus that catalyzes nucleophilic
addition of either l-cysteine (l-Cys) or bacillithiol
(BSH) to the antibiotic, resulting in a modified compound with no
bactericidal properties. The three-dimensional X-ray crystal structure
of FosB from S. aureus (FosBSa) has been determined to a resolution of 1.15 Å. Cocrystallization
of FosBSa with either l-Cys or
BSH results in a disulfide bond between the exogenous thiol and the
active site Cys9 of the enzyme. An analysis of the structures suggests
that a highly conserved loop region of the FosB enzymes must change
conformation to bind fosfomycin. While two crystals of FosBSa contain Zn2+ in the active site, kinetic
analyses of FosBSa indicated that the
enzyme is inhibited by Zn2+ for l-Cys transferase
activity and only marginally active for BSH transferase activity.
Fosfomycin-treated disk diffusion assays involving S. aureus Newman and the USA300 JE2 methicillin-resistant S. aureus demonstrate a marked increase in the sensitivity of the organism
to the antibiotic in either the BSH or FosB null strains, indicating
that both are required for survival of the organism in the presence
of the antibiotic. This work identifies FosB as a primary fosfomycin-modifying
pathway of S. aureus and establishes the enzyme as
a potential therapeutic target for increased efficacy of fosfomycin
against the pathogen.
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Affiliation(s)
- Matthew K Thompson
- Department of Biochemistry, Vanderbilt University School of Medicine , Nashville, Tennessee 37232, United States
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22
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Thompson MK, Keithly ME, Harp J, Cook PD, Jagessar KL, Sulikowski GA, Armstrong RN. Structural and chemical aspects of resistance to the antibiotic fosfomycin conferred by FosB from Bacillus cereus. Biochemistry 2013; 52:7350-62. [PMID: 24004181 DOI: 10.1021/bi4009648] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The fosfomycin resistance enzymes, FosB, from Gram-positive organisms, are M(2+)-dependent thiol tranferases that catalyze nucleophilic addition of either L-cysteine (L-Cys) or bacillithiol (BSH) to the antibiotic, resulting in a modified compound with no bacteriacidal properties. Here we report the structural and functional characterization of FosB from Bacillus cereus (FosB(Bc)). The overall structure of FosB(Bc), at 1.27 Å resolution, reveals that the enzyme belongs to the vicinal oxygen chelate (VOC) superfamily. Crystal structures of FosB(Bc) cocrystallized with fosfomycin and a variety of divalent metals, including Ni(2+), Mn(2+), Co(2+), and Zn(2+), indicate that the antibiotic coordinates to the active site metal center in an orientation similar to that found in the structurally homologous manganese-dependent fosfomycin resistance enzyme, FosA. Surface analysis of the FosB(Bc) structures show a well-defined binding pocket and an access channel to C1 of fosfomycin, the carbon to which nucleophilic addition of the thiol occurs. The pocket and access channel are appropriate in size and shape to accommodate L-Cys or BSH. Further investigation of the structures revealed that the fosfomycin molecule, anchored by the metal, is surrounded by a cage of amino acids that hold the antibiotic in an orientation such that C1 is centered at the end of the solvent channel, positioning the compound for direct nucleophilic attack by the thiol substrate. In addition, the structures of FosB(Bc) in complex with the L-Cys-fosfomycin product (1.55 Å resolution) and in complex with the bacillithiol-fosfomycin product (1.77 Å resolution) coordinated to a Mn(2+) metal in the active site have been determined. The L-Cys moiety of either product is located in the solvent channel, where the thiol has added to the backside of fosfomycin C1 located at the end of the channel. Concomitant kinetic analyses of FosB(Bc) indicated that the enzyme has a preference for BSH over L-Cys when activated by Mn(2+) and is inhibited by Zn(2+). The fact that Zn(2+) is an inhibitor of FosB(Bc) was used to obtain a ternary complex structure of the enzyme with both fosfomycin and L-Cys bound.
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Affiliation(s)
- Matthew K Thompson
- Department of Biochemistry, Vanderbilt University , Nashville, Tennessee 37232, United States
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23
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Plummer A, Thompson MK, Franzen S. Role of Polarity of the Distal Pocket in the Control of Inhibitor Binding in Dehaloperoxidase-Hemoglobin. Biochemistry 2013; 52:2218-27. [DOI: 10.1021/bi301509r] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ashlee Plummer
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina
27695, United States
| | - Matthew K. Thompson
- Department
of Biochemistry, Vanderbilt University Medical Center, Nashville, Tennessee
37232, United States
| | - Stefan Franzen
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina
27695, United States
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Schkolnik G, Utesch T, Zhao J, Jiang S, Thompson MK, Mroginski MA, Hildebrandt P, Franzen S. Catalytic efficiency of dehaloperoxidase A is controlled by electrostatics – application of the vibrational Stark effect to understand enzyme kinetics. Biochem Biophys Res Commun 2013; 430:1011-5. [DOI: 10.1016/j.bbrc.2012.12.047] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 12/10/2012] [Indexed: 11/17/2022]
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25
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Franzen S, Thompson MK, Ghiladi RA. The dehaloperoxidase paradox. Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics 2012; 1824:578-88. [DOI: 10.1016/j.bbapap.2011.12.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2011] [Revised: 12/20/2011] [Accepted: 12/23/2011] [Indexed: 12/01/2022]
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D'Antonio EL, D'Antonio J, de Serrano V, Gracz H, Thompson MK, Ghiladi RA, Bowden EF, Franzen S. Functional consequences of the creation of an Asp-His-Fe triad in a 3/3 globin. Biochemistry 2011; 50:9664-80. [PMID: 21950839 DOI: 10.1021/bi201368u] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The proximal side of dehaloperoxidase-hemoglobin A (DHP A) from Amphitrite ornata has been modified via site-directed mutagenesis of methionine 86 into aspartate (M86D) to introduce an Asp-His-Fe triad charge relay. X-ray crystallographic structure determination of the metcyano forms of M86D [Protein Data Bank (PDB) entry 3MYN ] and M86E (PDB entry 3MYM ) mutants reveal the structural origins of a stable catalytic triad in DHP A. A decrease in the rate of H(2)O(2) activation as well as a lowered reduction potential versus that of the wild-type enzyme was observed in M86D. One possible explanation for the significantly lower activity is an increased affinity for the distal histidine in binding to the heme Fe to form a bis-histidine adduct. Resonance Raman spectroscopy demonstrates a pH-dependent ligation by the distal histidine in M86D, which is indicative of an increased trans effect. At pH 5.0, the heme Fe is five-coordinate, and this structure resembles the wild-type DHP A resting state. However, at pH 7.0, the distal histidine appears to form a six-coordinate ferric bis-histidine (hemichrome) adduct. These observations can be explained by the effect of the increased positive charge on the heme Fe on the formation of a six-coordinate low-spin adduct, which inhibits the ligation and activation of H(2)O(2) as required for peroxidase activity. The results suggest that the proximal charge relay in peroxidases regulate the redox potential of the heme Fe but that the trans effect is a carefully balanced property that can both activate H(2)O(2) and attract ligation by the distal histidine. To understand the balance of forces that modulate peroxidase reactivity, we studied three M86 mutants, M86A, M86D, and M86E, by spectroelectrochemistry and nuclear magnetic resonance spectroscopy of (13)C- and (15)N-labeled cyanide adducts as probes of the redox potential and of the trans effect in the heme Fe, both of which can be correlated with the proximity of negative charge to the N(δ) hydrogen of the proximal histidine, consistent with an Asp-His-Fe charge relay observed in heme peroxidases.
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Affiliation(s)
- Edward L D'Antonio
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
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27
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Thompson MK, Franzen S, Davis MF, Oliver RC, Krueger JK. Dehaloperoxidase-hemoglobin from Amphitrite ornata is primarily a monomer in solution. J Phys Chem B 2011; 115:4266-72. [PMID: 21417234 DOI: 10.1021/jp201156r] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The crystal structures of the dehaloperoxidase-hemoglobin from A. ornata (DHP A) each report a crystallographic dimer in the unit cell. Yet, the largest dimer interface observed is 450 Å(2), an area significantly smaller than the typical value of 1200-2000 Å(2) and in contrast to the extensive interface region of other known dimeric hemoglobins. To examine the oligomerization state of DHP A in solution, we used gel permeation by fast protein liquid chromatography and small-angle X-ray scattering (SAXS). Gel permeation experiments demonstrate that DHP A elutes as a monomer (15.5 kDa) and can be separated from green fluorescent protein, which has a molar mass of 27 kDa, near the 31 kDa expected for the DHP A dimer. By SAXS, we found that DHP A is primarily monomeric in solution, but with a detectable level of dimer (~10%), under all conditions studied up to a protein concentration of 3.0 mM. These concentrations are likely 10-100-fold lower than the K(d) for dimer formation. Additionally, there was no significant effect either on the overall conformation of DHP A or its monomer-dimer equilibrium upon addition of the DHP A inhibitor, 4-iodophenol.
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Affiliation(s)
- Matthew K Thompson
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, USA
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28
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Nicoletti FP, Thompson MK, Franzen S, Smulevich G. Degradation of sulfide by dehaloperoxidase-hemoglobin from Amphitrite ornata. J Biol Inorg Chem 2011; 16:611-9. [DOI: 10.1007/s00775-011-0762-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Accepted: 01/26/2011] [Indexed: 10/18/2022]
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29
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Thompson MK, Franzen S, Ghiladi RA, Reeder BJ, Svistunenko DA. Decay of Compound ES in Dehaloperoxidase-Hemoglobin. Biophys J 2011. [DOI: 10.1016/j.bpj.2010.12.1275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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30
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Plummer AM, Thompson MK, Franzen S. Making Substrates Out of Inhibitors: Distal Cavity Mutations in Dehaloperoxidase from Amphitrite Ornata. Biophys J 2011. [DOI: 10.1016/j.bpj.2010.12.1424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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31
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Thompson MK, Davis MF, de Serrano V, Nicoletti FP, Howes BD, Smulevich G, Franzen S. Internal binding of halogenated phenols in dehaloperoxidase-hemoglobin inhibits peroxidase function. Biophys J 2010; 99:1586-95. [PMID: 20816071 DOI: 10.1016/j.bpj.2010.05.041] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Revised: 05/11/2010] [Accepted: 05/17/2010] [Indexed: 10/19/2022] Open
Abstract
Dehaloperoxidase (DHP) from the annelid Amphitrite ornata is a catalytically active hemoglobin-peroxidase that possesses a unique internal binding cavity in the distal pocket above the heme. The previously published crystal structure of DHP shows 4-iodophenol bound internally. This led to the proposal that the internal binding site is the active site for phenol oxidation. However, the native substrate for DHP is 2,4,6-tribromophenol, and all attempts to bind 2,4,6-tribromophenol in the internal site under physiological conditions have failed. Herein, we show that the binding of 4-halophenols in the internal pocket inhibits enzymatic function. Furthermore, we demonstrate that DHP has a unique two-site competitive binding mechanism in which the internal and external binding sites communicate through two conformations of the distal histidine of the enzyme, resulting in nonclassical competitive inhibition. The same distal histidine conformations involved in DHP function regulate oxygen binding and release during transport and storage by hemoglobins and myoglobins. This work provides further support for the hypothesis that DHP possesses an external binding site for substrate oxidation, as is typical for the peroxidase family of enzymes.
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Affiliation(s)
- Matthew K Thompson
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina, USA
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Thompson MK, Franzen S, Ghiladi RA, Reeder BJ, Svistunenko DA. Compound ES of Dehaloperoxidase Decays via Two Alternative Pathways Depending on the Conformation of the Distal Histidine. J Am Chem Soc 2010; 132:17501-10. [DOI: 10.1021/ja106620q] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Matthew K. Thompson
- Department of Chemistry, North Carolina State University, Box 8204, Raleigh, North Carolina 27695-8204, United States, and Department of Biological Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom
| | - Stefan Franzen
- Department of Chemistry, North Carolina State University, Box 8204, Raleigh, North Carolina 27695-8204, United States, and Department of Biological Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom
| | - Reza A. Ghiladi
- Department of Chemistry, North Carolina State University, Box 8204, Raleigh, North Carolina 27695-8204, United States, and Department of Biological Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom
| | - Brandon J. Reeder
- Department of Chemistry, North Carolina State University, Box 8204, Raleigh, North Carolina 27695-8204, United States, and Department of Biological Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom
| | - Dimitri A. Svistunenko
- Department of Chemistry, North Carolina State University, Box 8204, Raleigh, North Carolina 27695-8204, United States, and Department of Biological Sciences, University of Essex, Colchester CO4 3SQ, United Kingdom
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Ma H, Thompson MK, Gaff J, Franzen S. Kinetic Analysis of a Naturally Occurring Bioremediation Enzyme: Dehaloperoxidase-Hemoglobin from Amphitrite ornata. J Phys Chem B 2010; 114:13823-9. [DOI: 10.1021/jp1014516] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Huan Ma
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, and Department of Chemistry, Zhejiang University, Hangzhou, China
| | - Matthew K. Thompson
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, and Department of Chemistry, Zhejiang University, Hangzhou, China
| | - John Gaff
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, and Department of Chemistry, Zhejiang University, Hangzhou, China
| | - Stefan Franzen
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, and Department of Chemistry, Zhejiang University, Hangzhou, China
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D'Antonio J, D'Antonio EL, Thompson MK, Bowden EF, Franzen S, Smirnova T, Ghiladi RA. Spectroscopic and mechanistic investigations of dehaloperoxidase B from Amphitrite ornata. Biochemistry 2010; 49:6600-16. [PMID: 20545299 DOI: 10.1021/bi100407v] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dehaloperoxidase (DHP) from the terebellid polychaete Amphitrite ornata is a bifunctional enzyme that possesses both hemoglobin and peroxidase activities. Of the two DHP isoenzymes identified to date, much of the recent focus has been on DHP A, whereas very little is known pertaining to the activity, substrate specificity, mechanism of function, or spectroscopic properties of DHP B. Herein, we report the recombinant expression and purification of DHP B, as well as the details of our investigations into its catalytic cycle using biochemical assays, stopped-flow UV-visible, resonance Raman, and rapid freeze-quench electron paramagnetic resonance spectroscopies, and spectroelectrochemistry. Our experimental design reveals mechanistic insights and kinetic descriptions of the dehaloperoxidase mechanism which have not been previously reported for isoenzyme A. Namely, we demonstrate a novel reaction pathway in which the products of the oxidative dehalogenation of trihalophenols (dihaloquinones) are themselves capable of inducing formation of oxyferrous DHP B, and an updated catalytic cycle for DHP is proposed. We further demonstrate that, unlike the traditional monofunctional peroxidases, the oxyferrous state in DHP is a peroxidase-competent starting species, which suggests that the ferric oxidation state may not be an obligatory starting point for the enzyme. The data presented herein provide a link between the peroxidase and oxygen transport activities which furthers our understanding of how this bifunctional enzyme is able to unite its two inherent functions in one system.
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Affiliation(s)
- Jennifer D'Antonio
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
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Nicoletti FP, Thompson MK, Howes BD, Franzen S, Smulevich G. New Insights into the Role of Distal Histidine Flexibility in Ligand Stabilization of Dehaloperoxidase−Hemoglobin from Amphitrite ornata. Biochemistry 2010; 49:1903-12. [DOI: 10.1021/bi9020567] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Francesco P. Nicoletti
- Dipartimento di Chimica, Università di Firenze, Via della Lastruccia 3, I-50019 Sesto Fiorentino (FI), Italy
| | - Matthew K. Thompson
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, North Carolina 27695
| | - Barry D. Howes
- Dipartimento di Chimica, Università di Firenze, Via della Lastruccia 3, I-50019 Sesto Fiorentino (FI), Italy
| | - Stefan Franzen
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, North Carolina 27695
| | - Giulietta Smulevich
- Dipartimento di Chimica, Università di Firenze, Via della Lastruccia 3, I-50019 Sesto Fiorentino (FI), Italy
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Thompson MK, Parnell JM, Franzen S. Block the Inhibitor Binding Site in the Interior of Dehaloperoxidase from Amphitrite Ornata. Biophys J 2010. [DOI: 10.1016/j.bpj.2009.12.3513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Thompson MK, Vuchkov M, Kahwa IA. Cooperative processes governing formation of small pentanuclear lanthanide(III) nanoclusters and energy transport within and between them. Inorg Chem 2001; 40:4332-41. [PMID: 11487340 DOI: 10.1021/ic0102440] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Syntheses, lanthanide quantitative analyses, mass spectrometry and luminescence spectroscopy, and decay dynamics of crystals containing pentanuclear hetero-lanthanide(III) nanoclusters [(Ln'(5-x)Ln(x))(NO(3))(6)(mu(5)-OH)(mu(4)-L)(2)] (0 < or = x < or = 5), Ln' = Eu or Tb; Ln = La-Nd, Sm-Ho (hereafter Ln'(5-x) Ln(x)) were undertaken in search of information on factors governing self-assembly processes by which the clusters are formed and electronic interactions within and between them. The data obtained are consistent with the self-assembly of Ln'(5-x) Ln(x) nanoclusters being a concerted process featuring a profound expression of complementarity among mutually bridging [Ln(mu(4)-L](-) and [Ln(NO(3))(2)](+) components. The energy transport regime in crystals of Eu(5-x) Ln(x) is in the dynamic regime when x = 0 or Ln = La and, at 293 K, Ln = Dy, despite the presence of two crystallographically different Eu(3+) coordination environments which give rise to a doublet in the excitation and emission spectra of Eu(3+)((5)D(0)). The luminescence decay behavior of Eu(3+)((5)D(0)) in Eu(5-x) Ln(x) (Ln = Dy (for 77 K), Sm) is intermediate between the static and dynamic limits and reveals extensive electronic coupling among lanthanide ions, including many-body processes at relatively high Dy(3+) or Sm(3+) concentrations.
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Affiliation(s)
- M K Thompson
- Department of Chemistry and International Centre for Environmental and Nuclear Sciences, University of the West Indies Mona Campus, Kingston 7, Jamaica, West Indies
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Thompson MK, Tuma RF, Young WF. The effects of pentoxifylline on spinal cord blood flow after experimental spinal cord injury. J Assoc Acad Minor Phys 2000; 10:23-6. [PMID: 10826005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Previous clinical and experimental investigations have suggested that pentoxifylline, a methylxanthine, can improve cerebrovascular circulation and reduce cerebral edema in cerebrovascular disorders. Pentoxifylline's mechanism of action includes such rheologic effects as enhanced red cell deformability, alterations in leukocyte activation, and modification of coagulation parameters. The purpose of our investigation was to determine the effects of pentoxifylline in an experimental spinal cord injury model. A compression device was used to cause a reproducible spinal cord injury in adult female albino rats. Spinal cord blood flow was monitored using a laser Doppler flow meter pre- and postinjury for 4 hours. The experimental group (N = 7) was injected with pentoxifylline 10 minutes prior to injury. The control group (N = 5) received an identical protocol, except that this group was injected with an equal amount of saline. Results of this investigation revealed that pentoxifylline treatment significantly increased spinal cord blood flow. In the pentoxifylline-treated group, spinal cord blood flow was significantly higher from 120 to 240 minutes postinjury compared with that of the control group. We conclude that via its multiple physiologic effects, pentoxifylline significantly improves spinal cord blood flow in experimental spinal cord injury.
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Affiliation(s)
- M K Thompson
- Department of Neurosurgery, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA
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Thompson MK. Improved medical understanding of human health. Patient Educ Couns 1997; 31:165-169. [PMID: 9216359 DOI: 10.1016/s0738-3991(97)00992-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The time has come to examine aspects of health and disease on a broader basis than immediate cause and effect. Recognition of the biological processes of adaptation shaped by natural selection has become a requirement for improved understanding of human health in the modern environment, and the time has come for its incorporation into medical teaching and clinical practice.
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Abstract
Disease classes have hitherto been based on anatomical pathology and structural lesions belonging to an earlier ecological medical model involving classification. The diseases of ageing now coming to dominate clinical practice evolve across the clinical threshold in middle age parallel to changes occurring in the internal environment. The concept 'multiple pathology' used to describe the plural features of biological changes now requires new intellectual tools by which to understand overlap phenomena. Boolean algebra and Set Theory are proposed as the relevant enabling concepts, and their application to modern clinical practice is discussed.
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Thompson MK. Re-education via Darwinian medicine. Br J Gen Pract 1995; 45:692-3. [PMID: 8745877 PMCID: PMC1239489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
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Thompson MK. General practice at night. And finally, in the good old days.. BMJ 1995; 311:1028. [PMID: 7580617 PMCID: PMC2551028 DOI: 10.1136/bmj.311.7011.1028d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Thompson MK. Acute myocardial infarction. Br J Gen Pract 1995; 45:386. [PMID: 7612351 PMCID: PMC1239312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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Thompson MK. Assessment and screening of older people. J R Soc Med 1995; 88:120. [PMID: 7769591 PMCID: PMC1295120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
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Thompson MK. General Practice in the Post-Morgagni Era. Med Chir Trans 1992; 85:438-40. [PMID: 1404185 PMCID: PMC1293581 DOI: 10.1177/014107689208500803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Thompson MK. Site for immunising infants. BMJ 1992; 304:1178. [PMID: 1392808 PMCID: PMC1882108 DOI: 10.1136/bmj.304.6835.1178-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Thompson MK. Preventive care of elderly people. Br J Gen Pract 1992; 42:216. [PMID: 1389441 PMCID: PMC1372035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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Thompson MK. Randomized controlled trials. Br J Gen Pract 1991; 41:520. [PMID: 1807334 PMCID: PMC1371874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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