1
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Asmis R, Medrano MT, Chase Huizar C, Griffith WP, Forsthuber TG. Dietary Supplementation with 23-Hydroxy Ursolic Acid Reduces the Severity and Incidence of Acute Experimental Autoimmune Encephalomyelitis (EAE) in a Murine Model of Multiple Sclerosis. Nutrients 2024; 16:348. [PMID: 38337633 PMCID: PMC10856865 DOI: 10.3390/nu16030348] [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: 12/21/2023] [Revised: 01/15/2024] [Accepted: 01/22/2024] [Indexed: 02/12/2024] Open
Abstract
23-Hydroxy ursolic acid (23-OH UA) is a potent atheroprotective and anti-obesogenic phytochemical, with anti-inflammatory and inflammation-resolving properties. In this study, we examined whether dietary 23-OH UA protects mice against the acute onset and progression of experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis (MS). Female C57BL/6 mice were fed either a defined low-calorie maintenance diet (MD) or an MD supplemented with 0.2% wgt/wgt 23-OH UA for 5 weeks prior to actively inducing EAE and during the 30 days post-immunization. We observed no difference in the onset of EAE between the groups of mice, but ataxia and EAE disease severity were suppressed by 52% and 48%, respectively, and disease incidence was reduced by over 49% in mice that received 23-OH UA in their diet. Furthermore, disease-associated weight loss was strikingly ameliorated in 23-OH UA-fed mice. ELISPOT analysis showed no significant differences in frequencies of T cells producing IL-17 or IFN-γ between 23-OH UA-fed mice and control mice, suggesting that 23-OH UA does not appear to regulate peripheral T cell responses. In summary, our findings in EAE mice strongly suggest that dietary 23-OH UA may represent an effective oral adjunct therapy for the prevention and treatment of relapsing-remitting MS.
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Affiliation(s)
- Reto Asmis
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Megan T. Medrano
- Department of Molecular Microbiology and Immunology, University of Texas at San Antonio, San Antonio, TX 78249, USA; (M.T.M.)
| | - Carol Chase Huizar
- Department of Molecular Microbiology and Immunology, University of Texas at San Antonio, San Antonio, TX 78249, USA; (M.T.M.)
| | - Wendell P. Griffith
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Thomas G. Forsthuber
- Department of Molecular Microbiology and Immunology, University of Texas at San Antonio, San Antonio, TX 78249, USA; (M.T.M.)
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2
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Blank HM, Griffith WP, Polymenis M. Targeting APEX2 to the mRNA encoding fatty acid synthase β in yeast identifies interacting proteins that control its abundance in the cell cycle. Mol Biol Cell 2023; 34:br20. [PMID: 37792491 PMCID: PMC10848943 DOI: 10.1091/mbc.e23-05-0166] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 09/25/2023] [Accepted: 09/29/2023] [Indexed: 10/06/2023] Open
Abstract
Profiling the repertoire of proteins associated with a given mRNA during the cell cycle is unstudied. Furthermore, it is easier to ask and answer what mRNAs a specific protein might bind to than the other way around. Here, we implemented an RNA-centric proximity labeling technology at different points in the cell cycle in highly synchronous yeast cultures. To understand how the abundance of FAS1, encoding fatty acid synthase, peaks late in the cell cycle, we identified proteins that interact with the FAS1 transcript in a cell cycle-dependent manner. We used dCas13d-APEX2 fusions to target FAS1 and label nearby proteins, which were then identified by mass spectrometry. The glycolytic enzyme Tdh3p, a known RNA-binding protein, interacted with the FAS1 mRNA, and it was necessary for the periodic abundance of Fas1p in the cell cycle. These results point to unexpected connections between major metabolic pathways. They also underscore the role of mRNA-protein interactions for gene expression during cell division.
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Affiliation(s)
- Heidi M. Blank
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843
| | - Wendell P. Griffith
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX 78249
| | - Michael Polymenis
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843
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3
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Zheng H, Wang K, Faghihi I, Griffith WP, Arman H, Doyle MP. Diverse Reactions of Vinyl Diazo Compounds with Quinone Oxonium Ions, Quinone Imine Ketals, and Eschenmoser’s Salt. ACS Catal 2021. [DOI: 10.1021/acscatal.1c02674] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Haifeng Zheng
- Department of Chemistry, The University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, United States
| | - Kan Wang
- Department of Chemistry, The University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, United States
| | - Isa Faghihi
- Department of Chemistry, The University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, United States
| | - Wendell P. Griffith
- Department of Chemistry, The University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, United States
| | - Hadi Arman
- Department of Chemistry, The University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, United States
| | - Michael P. Doyle
- Department of Chemistry, The University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, United States
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4
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Su YL, Tram L, Wherritt D, Arman H, Griffith WP, Doyle MP. α-Amino Radical-Mediated Diverse Difunctionalization of Alkenes: Construction of C–C, C–N, and C–S Bonds. ACS Catal 2020. [DOI: 10.1021/acscatal.0c04243] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Yong-Liang Su
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Linh Tram
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Daniel Wherritt
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Hadi Arman
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Wendell P. Griffith
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Michael P. Doyle
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, Texas 78249, United States
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5
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Li J, Davis I, Griffith WP, Liu A. Formation of Monofluorinated Radical Cofactor in Galactose Oxidase through Copper-Mediated C-F Bond Scission. J Am Chem Soc 2020; 142:18753-18757. [PMID: 33091303 DOI: 10.1021/jacs.0c08992] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Galactose oxidase (GAO) contains a Cu(II)-ligand radical cofactor. The cofactor, which is autocatalytically generated through the oxidation of the copper, consists of a cysteine-tyrosine radical (Cys-Tyr•) as a copper ligand. The formation of the cross-linked thioether bond is accompanied by a C-H bond scission on Tyr272 with few details known thus far. Here, we report the genetic incorporation of 3,5-dichlorotyrosine (Cl2-Tyr) and 3,5-difluorotyrosine (F2-Tyr) to replace Tyr272 in the GAOV previously optimized for expression through directed evolution. The proteins with an unnatural tyrosine residue are catalytically competent. We determined the high-resolution crystal structures of the GAOV, Cl2-Tyr272, and F2-Tyr272 incorporated variants at 1.48, 1.23, and 1.80 Å resolution, respectively. The structural data showed only one halogen remained in the cofactor, indicating that an oxidative carbon-chlorine/fluorine bond scission has occurred during the autocatalytic process of cofactor biogenesis. Using hydroxyurea as a radical scavenger, the spin-coupled hidden Cu(II) was observed by EPR spectroscopy. Thus, the structurally defined catalytic center with genetic unnatural tyrosine substitution is in the radical containing form as in the wild-type, i.e., Cu(II)-(Cl-Tyr•-Cys) or Cu(II)-(F-Tyr•-Cys). These findings illustrate a previously unobserved C-F/C-Cl bond cleavage in biology mediated by a mononuclear copper center.
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Affiliation(s)
- Jiasong Li
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Ian Davis
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Wendell P Griffith
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Aimin Liu
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, Texas 78249, United States
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6
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Wang Y, Davis I, Chan Y, Naik SG, Griffith WP, Liu A. Characterization of the nonheme iron center of cysteamine dioxygenase and its interaction with substrates. J Biol Chem 2020; 295:11789-11802. [PMID: 32601061 DOI: 10.1074/jbc.ra120.013915] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [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: 04/16/2020] [Revised: 06/25/2020] [Indexed: 12/15/2022] Open
Abstract
Cysteamine dioxygenase (ADO) has been reported to exhibit two distinct biological functions with a nonheme iron center. It catalyzes oxidation of both cysteamine in sulfur metabolism and N-terminal cysteine-containing proteins or peptides, such as regulator of G protein signaling 5 (RGS5). It thereby preserves oxygen homeostasis in a variety of physiological processes. However, little is known about its catalytic center and how it interacts with these two types of primary substrates in addition to O2 Here, using electron paramagnetic resonance (EPR), Mössbauer, and UV-visible spectroscopies, we explored the binding mode of cysteamine and RGS5 to human and mouse ADO proteins in their physiologically relevant ferrous form. This characterization revealed that in the presence of nitric oxide as a spin probe and oxygen surrogate, both the small molecule and the peptide substrates coordinate the iron center with their free thiols in a monodentate binding mode, in sharp contrast to binding behaviors observed in other thiol dioxygenases. We observed a substrate-bound B-type dinitrosyl iron center complex in ADO, suggesting the possibility of dioxygen binding to the iron ion in a side-on mode. Moreover, we observed substrate-mediated reduction of the iron center from ferric to the ferrous oxidation state. Subsequent MS analysis indicated corresponding disulfide formation of the substrates, suggesting that the presence of the substrate could reactivate ADO to defend against oxidative stress. The findings of this work contribute to the understanding of the substrate interaction in ADO and fill a gap in our knowledge of the substrate specificity of thiol dioxygenases.
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Affiliation(s)
- Yifan Wang
- Department of Chemistry, University of Texas at San Antonio, Texas, USA
| | - Ian Davis
- Department of Chemistry, University of Texas at San Antonio, Texas, USA.,Department of Chemistry, Georgia State University, Atlanta, Georgia, USA
| | - Yan Chan
- Department of Chemistry, Georgia State University, Atlanta, Georgia, USA
| | - Sunil G Naik
- Department of Chemistry, University of Texas at San Antonio, Texas, USA
| | | | - Aimin Liu
- Department of Chemistry, University of Texas at San Antonio, Texas, USA .,Department of Chemistry, Georgia State University, Atlanta, Georgia, USA
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7
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Wang Y, Davis I, Shin I, Wherritt DJ, Griffith WP, Dornevil K, Colabroy KL, Liu A. Biocatalytic Carbon-Hydrogen and Carbon-Fluorine Bond Cleavage through Hydroxylation Promoted by a Histidyl-Ligated Heme Enzyme. ACS Catal 2019; 9:4764-4776. [PMID: 31355048 DOI: 10.1021/acscatal.9b00231] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
LmbB2 is a peroxygenase-like enzyme that hydroxylates L-tyrosine to L-3,4-dihydroxyphenylalanine (DOPA) in the presence of hydrogen peroxide. However, its heme cofactor is ligated by a proximal histidine, not cysteine. We show that LmbB2 can oxidize L-tyrosine analogs with ring-deactivated substituents such as 3-nitro-, fluoro-, chloro-, iodo-L-tyrosine. We also found that the 4-hydroxyl group of the substrate is essential for reacting with the heme-based oxidant and activating the aromatic C-H bond. The most interesting observation of this study was obtained with 3-fluoro-L-tyrosine as a substrate and mechanistic probe. The LmbB2-mediated catalytic reaction yielded two hydroxylated products with comparable populations, i.e., oxidative C-H bond cleavage at C5 to generate 3-fluoro-5-hydroxyl-L-tyrosine and oxygenation at C3 concomitant with a carbon-fluorine bond cleavage to yield DOPA and fluoride. An iron protein-mediated hydroxylation on both C-H and C-F bonds with multiple turnovers is unprecedented. Thus, this finding reveals a significant potential of biocatalysis in C-H/C-X bond (X = halogen) cleavage. Further 18O-labeling results suggest that the source of oxygen for hydroxylation is a peroxide, and that a commonly expected oxidation by a high-valent iron intermediate followed by hydrolysis is not supported for the C-F bond cleavage. Instead, the C-F bond cleavage is proposed to be initiated by a nucleophilic aromatic substitution mediated by the iron-hydroperoxo species. Based on the experimental results, two mechanisms are proposed to explain how LmbB2 hydroxylates the substrate and cleaves C-H/C-F bond. This study broadens the understanding of heme enzyme catalysis and sheds light on enzymatic applications in medicinal and environmental fields.
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Affiliation(s)
- Yifan Wang
- Department of Chemistry, University of Texas, San Antonio, Texas 78249, United States
| | - Ian Davis
- Department of Chemistry, University of Texas, San Antonio, Texas 78249, United States
| | - Inchul Shin
- Department of Chemistry, University of Texas, San Antonio, Texas 78249, United States
| | - Daniel J. Wherritt
- Department of Chemistry, University of Texas, San Antonio, Texas 78249, United States
| | - Wendell P. Griffith
- Department of Chemistry, University of Texas, San Antonio, Texas 78249, United States
| | - Kednerlin Dornevil
- Department of Chemistry, University of Texas, San Antonio, Texas 78249, United States
| | - Keri L. Colabroy
- Department of Chemistry, Muhlenberg College, Allentown, Pennsylvania 18104, United States
| | - Aimin Liu
- Department of Chemistry, University of Texas, San Antonio, Texas 78249, United States
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8
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Wang Y, Griffith WP, Li J, Koto T, Wherritt DJ, Fritz E, Liu A. Cofactor Biogenesis in Cysteamine Dioxygenase: C−F Bond Cleavage with Genetically Incorporated Unnatural Tyrosine. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201803907] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Yifan Wang
- Department of Chemistry The University of Texas at San Antonio San Antonio TX USA
| | - Wendell P. Griffith
- Department of Chemistry The University of Texas at San Antonio San Antonio TX USA
| | - Jiasong Li
- Department of Chemistry The University of Texas at San Antonio San Antonio TX USA
| | - Teruaki Koto
- Department of Chemistry The University of Texas at San Antonio San Antonio TX USA
| | - Daniel J. Wherritt
- Department of Chemistry The University of Texas at San Antonio San Antonio TX USA
| | - Elizabeth Fritz
- Department of Chemistry The University of Texas at San Antonio San Antonio TX USA
| | - Aimin Liu
- Department of Chemistry The University of Texas at San Antonio San Antonio TX USA
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9
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Wang Y, Griffith WP, Li J, Koto T, Wherritt DJ, Fritz E, Liu A. Cofactor Biogenesis in Cysteamine Dioxygenase: C-F Bond Cleavage with Genetically Incorporated Unnatural Tyrosine. Angew Chem Int Ed Engl 2018; 57:8149-8153. [PMID: 29752763 DOI: 10.1002/anie.201803907] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [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: 04/02/2018] [Indexed: 12/22/2022]
Abstract
Cysteamine dioxygenase (ADO) is a thiol dioxygenase whose study has been stagnated by the ambiguity as to whether or not it possesses an anticipated protein-derived cofactor. Reported herein is the discovery and elucidation of a Cys-Tyr cofactor in human ADO, crosslinked between Cys220 and Tyr222 through a thioether (C-S) bond. By genetically incorporating an unnatural amino acid, 3,5-difluoro-tyrosine (F2 -Tyr), specifically into Tyr222 of human ADO, an autocatalytic oxidative carbon-fluorine bond activation and fluoride release were identified by mass spectrometry and 19 F NMR spectroscopy. These results suggest that the cofactor biogenesis is executed by a powerful oxidant during an autocatalytic process. Unlike that of cysteine dioxygenase, the crosslinking results in a minimal structural change of the protein and it is not detectable by routine low-resolution techniques. Finally, a new sequence motif, C-X-Y-Y(F), is proposed for identifying the Cys-Tyr crosslink.
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Affiliation(s)
- Yifan Wang
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Wendell P Griffith
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Jiasong Li
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Teruaki Koto
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Daniel J Wherritt
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Elizabeth Fritz
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Aimin Liu
- Department of Chemistry, The University of Texas at San Antonio, San Antonio, TX, USA
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10
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Shin I, Ambler BR, Wherritt D, Griffith WP, Maldonado AC, Altman RA, Liu A. Stepwise O-Atom Transfer in Heme-Based Tryptophan Dioxygenase: Role of Substrate Ammonium in Epoxide Ring Opening. J Am Chem Soc 2018; 140:4372-4379. [PMID: 29506384 PMCID: PMC5874177 DOI: 10.1021/jacs.8b00262] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [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: 12/19/2022]
Abstract
Heme-based tryptophan dioxygenases are established immunosuppressive metalloproteins with significant biomedical interest. Here, we synthesized two mechanistic probes to specifically test if the α-amino group of the substrate directly participates in a critical step of the O atom transfer during catalysis in human tryptophan 2,3-dioxygenase (TDO). Substitution of the nitrogen atom of the substrate to a carbon (probe 1) or oxygen (probe 2) slowed the catalytic step following the first O atom transfer such that transferring the second O atom becomes less likely to occur, although the dioxygenated products were observed with both probes. A monooxygenated product was also produced from probe 2 in a significant quantity. Analysis of this new product by HPLC coupled UV-vis spectroscopy, high-resolution mass spectrometry, 1H NMR, 13C NMR, HSQC, HMBC, and infrared (IR) spectroscopies concluded that this monooxygenated product is a furoindoline compound derived from an unstable epoxyindole intermediate. These results prove that small molecules can manipulate the stepwise O atom transfer reaction of TDO and provide a showcase for a tunable mechanism by synthetic compounds. The product analysis results corroborate the presence of a substrate-based epoxyindole intermediate during catalysis and provide the first substantial experimental evidence for the involvement of the substrate α-amino group in the epoxide ring-opening step during catalysis. This combined synthetic, biochemical, and biophysical study establishes the catalytic role of the α-amino group of the substrate during the O atom transfer reactions and thus represents a substantial advance to the mechanistic comprehension of the heme-based tryptophan dioxygenases.
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Affiliation(s)
- Inchul Shin
- Department of Chemistry, University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Brett R. Ambler
- Department of Medicinal Chemistry, The University of Kansas, Lawrence, Kansas 66045, United States
| | - Daniel Wherritt
- Department of Chemistry, University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Wendell P. Griffith
- Department of Chemistry, University of Texas at San Antonio, San Antonio, Texas 78249, United States
| | - Amanda C. Maldonado
- Department of Medicinal Chemistry, The University of Kansas, Lawrence, Kansas 66045, United States
| | - Ryan A. Altman
- Department of Medicinal Chemistry, The University of Kansas, Lawrence, Kansas 66045, United States
| | - Aimin Liu
- Department of Chemistry, University of Texas at San Antonio, San Antonio, Texas 78249, United States
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11
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Yoshimoto FK, Arman HD, Griffith WP, Yan F, Wherritt DJ. Chemical synthesis of 7α-hydroxypregnenolone, a neuroactive steroid that stimulates locomotor activity. Steroids 2017; 128:50-57. [PMID: 29061488 DOI: 10.1016/j.steroids.2017.10.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 09/25/2017] [Accepted: 10/10/2017] [Indexed: 02/07/2023]
Abstract
7α-Hydroxypregnenolone is an endogenous neuroactive steroid that stimulates locomotor activity. A synthesis of 7α-hydroxypregnenolone from pregnenolone, which takes advantage of an orthogonal protecting group strategy, is described. In detail, the C7-position was oxidized with CrO3 and 3,5-dimethylpyrazole to yield a 7-keto steroid intermediate. The resulting 7-ketone was stereoselectively reduced to the 7α-hydroxy group with lithium tri-sec-butylborohydride. In contrast, reduction of the same 7-ketone intermediate with NaBH4 resulted in primarily the 7β-hydroxy epimer. Furthermore, in an alternative route to the target compound, the 7α-hydroxy group was successfully incorporated by direct C-H allylic benzoyloxylation of pregnenolone-3-acetate with CuBr and tert-butyl peroxybenzoate followed by saponification. The disclosed syntheses to 7-oxygenated steroids are amenable to potentially obtain other biologically active sterols and steroids.
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Affiliation(s)
- Francis K Yoshimoto
- Department of Chemistry at the University of Texas at San Antonio, TX 78249-0698, United States.
| | - Hadi D Arman
- Department of Chemistry at the University of Texas at San Antonio, TX 78249-0698, United States
| | - Wendell P Griffith
- Department of Chemistry at the University of Texas at San Antonio, TX 78249-0698, United States
| | - Fangzhi Yan
- Department of Chemistry at the University of Texas at San Antonio, TX 78249-0698, United States
| | - Daniel J Wherritt
- Department of Chemistry at the University of Texas at San Antonio, TX 78249-0698, United States
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12
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Renthal R, Manghnani L, Bernal S, Qu Y, Griffith WP, Lohmeyer K, Guerrero FD, Borges LMF, Pérez de León A. The chemosensory appendage proteome of Amblyomma americanum (Acari: Ixodidae) reveals putative odorant-binding and other chemoreception-related proteins. Insect Sci 2017; 24:730-742. [PMID: 27307202 DOI: 10.1111/1744-7917.12368] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/29/2016] [Indexed: 06/06/2023]
Abstract
Proteomic analyses were done on 2 chemosensory appendages of the lone star tick, Amblyomma americanum. Proteins in the fore tarsi, which contain the olfactory Haller's organ, and in the palps, that include gustatory sensilla, were compared with proteins in the third tarsi. Also, male and female ticks were compared. Proteins were identified by sequence similarity to known proteins, and by 3-dimensional homology modeling. Proteomic data were also compared with organ-specific transcriptomes from the tick Rhipicephalus microplus. The fore tarsi express a lipocalin not found in the third tarsi or palps. The fore tarsi and palps abundantly express 2 proteins, which are similar to insect odorant-binding proteins (OBPs). Compared with insect OBPs, the tick OBP-like sequences lacked the cysteine absent in C-minus OBPs, and 1 tick OBP-like sequence had additional cysteines that were similar to C-plus OBPs. Four proteins similar to the antibiotic protein microplusin were found: 2 exclusively expressed in the fore tarsi and 1 exclusively expressed in the palps. These proteins lack the microplusin copper-binding site, but they are modeled to have a significant internal cavity, potentially a ligand-binding site. Proteins similar to the dust mite allergens Der p7 and Der f 7 were found differentially expressed in female fore tarsi. A protein exclusively expressed in the fore tarsi has similarities to Neto, which is known to be involved in clustering of ionotropic glutamate receptors. These results constitute the first report of OBP-like protein sequences in ticks and point to several research avenues on tick chemosensory reception.
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Affiliation(s)
- Robert Renthal
- Department of Biology, University of Texas at San Antonio, San Antonio, TX, 78249, USA
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX, 78229, USA
| | - Leena Manghnani
- Department of Biology, University of Texas at San Antonio, San Antonio, TX, 78249, USA
| | - Sandra Bernal
- Department of Biology, University of Texas at San Antonio, San Antonio, TX, 78249, USA
| | - Yanyan Qu
- RCMI Protein Biomarkers Core, University of Texas at San Antonio, San Antonio, TX, 78249, USA
| | - Wendell P Griffith
- RCMI Protein Biomarkers Core, University of Texas at San Antonio, San Antonio, TX, 78249, USA
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX, 78249, USA
| | - Kim Lohmeyer
- USDA-ARS Knipling-Bushland U.S. Livestock Insects Research Laboratory, Veterinary Pest Genomics Center, Kerrville, TX, 78029, USA
| | - Felix D Guerrero
- USDA-ARS Knipling-Bushland U.S. Livestock Insects Research Laboratory, Veterinary Pest Genomics Center, Kerrville, TX, 78029, USA
| | - Lígia M F Borges
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Adalberto Pérez de León
- USDA-ARS Knipling-Bushland U.S. Livestock Insects Research Laboratory, Veterinary Pest Genomics Center, Kerrville, TX, 78029, USA
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13
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Alvarez MM, Chen J, Plascencia-Villa G, Black DM, Griffith WP, Garzon IL, José Yacamán M, Demeler B, Whetten RL. Hidden Components in Aqueous "Gold-144" Fractionated by PAGE: High-Resolution Orbitrap ESI-MS Identifies the Gold-102 and Higher All-Aromatic Au-pMBA Cluster Compounds. J Phys Chem B 2016; 120:6430-8. [PMID: 27275518 PMCID: PMC6666316 DOI: 10.1021/acs.jpcb.6b04525] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [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: 12/16/2022]
Abstract
Experimental and theoretical evidence reveals the resilience and stability of the larger aqueous gold clusters protected with p-mercaptobenzoic acid ligands (pMBA) of composition Aun(pMBA)p or (n, p). The Au144(pMBA)60, (144, 60), or gold-144 aqueous gold cluster is considered special because of its high symmetry, abundance, and icosahedral structure as well as its many potential uses in material and biological sciences. Yet, to this date, direct confirmation of its precise composition and total structure remains elusive. Results presented here from characterization via high-resolution electrospray ionization mass spectrometry on an Orbitrap instrument confirm Au102(pMBA)44 at isotopic resolution. Further, what usually appears as a single band for (144, 60) in electrophoresis (PAGE) is shown to also contain the (130, 50), recently determined to have a truncated-decahedral structure, and a (137, 56) component in addition to the dominant (144, 60) compound of chiral-icosahedral structure. This finding is significant in that it reveals the existence of structures never before observed in all-aromatic water-soluble species while pointing out the path toward elucidation of the thermodynamic control of protected gold nanocrystal formation.
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Affiliation(s)
- Marcos M. Alvarez
- Department of Physics & Astronomy, University of Texas, San Antonio, TX, 78249, USA
| | - Jenny Chen
- ThermoFisher Scientific 355 River Oaks Pkwy, San Jose, CA 95134, USA
| | | | - David M. Black
- Department of Physics & Astronomy, University of Texas, San Antonio, TX, 78249, USA
| | - Wendell P. Griffith
- RCMI Protein Biomarkers Core. University of Texas, San Antonio, Texas, 78249, USA
| | - Ignacio L. Garzon
- Department of Physics & Astronomy, University of Texas, San Antonio, TX, 78249, USA
- Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 20-364, 01000 México, D. F, México
| | - Miguel José Yacamán
- Department of Physics & Astronomy, University of Texas, San Antonio, TX, 78249, USA
| | - Borries Demeler
- Department of Biochemistry. University of Texas Health Science Center, San Antonio, Texas, 78229
| | - Robert L. Whetten
- Department of Physics & Astronomy, University of Texas, San Antonio, TX, 78249, USA
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Wickramasinghe S, Atnagulov A, Conn BE, Yoon B, Barnett RN, Griffith WP, Landman U, Bigioni TP. Correction to “M3Ag17(SPh)12 Nanoparticles and Their Structure Prediction”. J Am Chem Soc 2016; 138:6312. [DOI: 10.1021/jacs.6b03556] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
The oxidation of glucagon, which is one of the key hormones in glucose homeostasis, was studied at electrodes modified with carbon nanotubes (CNT) that were dispersed in a polysaccharide adhesive chitosan (CHIT). Such electrodes displayed improved resistance to fouling, which allowed for the investigation of both the electrolysis/mass spectrometry and electroanalysis of glucagon. The off-line electrospray ionization and tandem mass spectrometric analyses showed that the -4 Da mass change to glucagon upon electrolysis at CNT was due to the electrooxidation of its tryptophan (W25) and dityrosine (Y10, Y13) residues. The methionine residue of glucagon did not contribute to its oxidation. The amperometric determination of glucagon yielded the limit of detection equal to ∼20 nM (E = 0.800 V, pH 7.40, S/N = 3), sensitivity of 0.46 A M(-1) cm(-2), linear dynamic range up to 2.0 μM (R(2) = 0.998), response time <5 s, and good signal stability. Free tryptophan and tyrosine yielded comparable analytical figures of merit. The direct amperometric determination of unlabeled glucagon at CHIT-CNT electrodes is the first example of a rapid alternative to the complex analytical assays of this peptide.
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Affiliation(s)
- Sushma Karra
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX 78249-0698, USA.
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Wickramasinghe S, Atnagulov A, Yoon B, Barnett RN, Griffith WP, Landman U, Bigioni TP. M3Ag17(SPh)12 Nanoparticles and Their Structure Prediction. J Am Chem Soc 2015; 137:11550-3. [DOI: 10.1021/jacs.5b05422] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | - Bokwon Yoon
- School
of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, United States
| | - Robert N. Barnett
- School
of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, United States
| | | | - Uzi Landman
- School
of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, United States
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17
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Desireddy A, Conn BE, Guo J, Yoon B, Barnett RN, Monahan BM, Kirschbaum K, Griffith WP, Whetten RL, Landman U, Bigioni TP. Ultrastable silver nanoparticles. Nature 2013; 501:399-402. [DOI: 10.1038/nature12523] [Citation(s) in RCA: 872] [Impact Index Per Article: 79.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Accepted: 08/01/2013] [Indexed: 12/22/2022]
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18
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Desireddy A, Kumar S, Guo J, Bolan MD, Griffith WP, Bigioni TP. Temporal stability of magic-number metal clusters: beyond the shell closing model. Nanoscale 2013; 5:2036-2044. [PMID: 23370266 DOI: 10.1039/c3nr33705g] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The anomalous stability of magic-number metal clusters has been associated with closed geometric and electronic shells and the opening of HOMO-LUMO gaps. Despite this enhanced stability, magic-number clusters are known to decay and react in the condensed phase to form other products. Improving our understanding of their decay mechanisms and developing strategies to control or eliminate cluster instability is a priority, to develop a more complete theory of their stability, to avoid studying mixtures of clusters produced by the decay of purified materials, and to enable technology development. Silver clusters are sufficiently reactive to facilitate the study of the ambient temporal stability of magic-number metal clusters and to begin to understand their decay mechanisms. Here, the solution phase stability of a series of silver:glutathione (Ag:SG) clusters was studied as a function of size, pH and chemical environment. Cluster stability was found to be a non-monotonic function of size. Electrophoretic separations showed that the dominant mechanism involved the redistribution of mass toward smaller sizes, where the products were almost exclusively previously known cluster sizes. Optical absorption spectra showed that the smaller clusters evolved toward the two most stable cluster sizes. The net surface charge was found to play an important role in cluster stabilization although charge screening had no effect on stability, contrary to DLVO theory. The decay mechanism was found to involve the loss of Ag(+) ions and silver glutathionates. Clusters could be stabilized by the addition of Ag(+) ions and destabilized by either the addition of glutathione or the removal of Ag(+) ions. Clusters were also found to be most stable in near neutral pH, where they had a net negative surface charge. These results provide new mechanistic insights into the control of post-synthesis stability and chemical decay of magic-number metal clusters, which could be used to develop design principles for synthesizing specific cluster species.
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Affiliation(s)
- Anil Desireddy
- Department of Chemistry, The University of Toledo, Toledo, OH 43606, USA
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Guo J, Kumar S, Bolan M, Desireddy A, Bigioni TP, Griffith WP. Mass Spectrometric Identification of Silver Nanoparticles: The Case of Ag32(SG)19. Anal Chem 2012; 84:5304-8. [DOI: 10.1021/ac300536j] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Jingshu Guo
- Department of Chemistry, University of Toledo, Toledo, Ohio 43606, United States
| | - Santosh Kumar
- Department of Chemistry, University of Toledo, Toledo, Ohio 43606, United States
| | - Michael Bolan
- Department of Chemistry, University of Toledo, Toledo, Ohio 43606, United States
| | - Anil Desireddy
- Department of Chemistry, University of Toledo, Toledo, Ohio 43606, United States
| | - Terry P. Bigioni
- Department of Chemistry, University of Toledo, Toledo, Ohio 43606, United States
| | - Wendell P. Griffith
- Department of Chemistry, University of Toledo, Toledo, Ohio 43606, United States
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Hersman E, Nelson DM, Griffith WP, Jelinek C, Cotter RJ. Analysis of Histone Modifications from Tryptic Peptides of Deuteroacetylated Isoforms. Int J Mass Spectrom 2012; 312:5-16. [PMID: 22389584 PMCID: PMC3289288 DOI: 10.1016/j.ijms.2011.04.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The in vitro deuteroacetylation of histones obtained from biological sources has been used previously in bottom-up mass spectrometry analyses to quantitate the percent of endogenous acetylation of specific lysine sites and/or peptides. In this report, derivatization of unmodified lysine residues on histones is used in combination with high performance mass spectrometry, including combined HPLC MS/MS, to distinguish and quantitate endogenously acetylated isoforms occurring within the same tryptic peptide sequence and to extend this derivatization strategy to other post-translational modifications, specifically methylation, dimethylation and trimethylation. The in vitro deuteroacetylation of monomethylated lysine residues is observed, though dimethylated or trimethylated residues are not derivatised. Comparison of the relative intensities ascribed to the deuteroacetylated and monomethylated species with the deuteroacetylated but unmethylated analog, provides an opportunity to estimate the percent of methylation at that site. In addition to the observed fragmentation patterns, the very high mass accuracy available on the Orbitrap mass spectrometer can be used to confirm the structural isoforms, and in particular to distinguish between trimethylated and acetylated species.
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Affiliation(s)
- Elisabeth Hersman
- Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205
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21
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Dumont Q, Donaldson DL, Griffith WP. Screening Method for Isopeptides from Small Ubiquitin-Related Modifier-Conjugated Proteins by Ion Mobility Mass Spectrometry. Anal Chem 2011; 83:9638-42. [DOI: 10.1021/ac202505r] [Citation(s) in RCA: 9] [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)
- Quentin Dumont
- Department of Chemistry, University of Toledo, Toledo, Ohio 43606, United States
| | - David L. Donaldson
- Department of Chemistry, University of Toledo, Toledo, Ohio 43606, United States
| | - Wendell P. Griffith
- Department of Chemistry, University of Toledo, Toledo, Ohio 43606, United States
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Dignam JD, Guo J, Griffith WP, Garbett NC, Holloway A, Mueser T. Allosteric interaction of nucleotides and tRNA(ala) with E. coli alanyl-tRNA synthetase. Biochemistry 2011; 50:9886-900. [PMID: 21985608 DOI: 10.1021/bi2012004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [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
Alanyl-tRNA synthetase, a dimeric class 2 aminoacyl-tRNA synthetase, activates glycine and serine at significant rates. An editing activity hydrolyzes Gly-tRNA(ala) and Ser-tRNA(ala) to ensure fidelity of aminoacylation. Analytical ultracentrifugation demonstrates that the enzyme is predominately a dimer in solution. ATP binding to full length enzyme (ARS875) and to an N-terminal construct (ARS461) is endothermic (ΔH = 3-4 kcal mol(-1)) with stoichiometries of 1:1 for ARS461 and 2:1 for full-length dimer. Binding of aminoacyl-adenylate analogues, 5'-O-[N-(L-alanyl)sulfamoyl]adenosine (ASAd) and 5'-O-[N-(L-glycinyl)sulfamoyl]adenosine (GSAd), are exothermic; ASAd exhibits a large negative heat capacity change (ΔC(p) = 0.48 kcal mol(-1) K(-1)). Modification of alanyl-tRNA synthetase with periodate-oxidized tRNA(ala) (otRNA(ala)) generates multiple, covalent, enzyme-tRNA(ala) products. The distribution of these products is altered by ATP, ATP and alanine, and aminoacyl-adenylate analogues (ASAd and GSAd). Alanyl-tRNA synthetase was modified with otRNA(ala), and tRNA-peptides from tryptic digests were purified by ion exchange chromatography. Six peptides linked through a cyclic dehydromoropholino structure at the 3'-end of tRNA(ala) were sequenced by mass spectrometry. One site lies in the N-terminal adenylate synthesis domain (residue 74), two lie in the opening to the editing site (residues 526 and 585), and three (residues 637, 639, and 648) lie on the back side of the editing domain. At least one additional modification site was inferred from analysis of modification of ARS461. The location of the sites modified by otRNA(ala) suggests that there are multiple modes of interaction of tRNA(ala) with the enzyme, whose distribution is influenced by occupation of the ATP binding site.
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Affiliation(s)
- John David Dignam
- Department of Biochemistry and Cancer Biology, University of Toledo College of Medicine, Toledo, Ohio 43614, United States.
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Mueser TC, Griffith WP, Kovalevsky AY, Guo J, Seaver S, Langan P, Hanson BL. Hemoglobin redux: combining neutron and X-ray diffraction with mass spectrometry to analyse the quaternary state of oxidized hemoglobins. Acta Crystallogr D Biol Cryst 2010; 66:1249-56. [PMID: 21041946 PMCID: PMC2967423 DOI: 10.1107/s090744491002545x] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2010] [Accepted: 06/28/2010] [Indexed: 11/10/2022]
Abstract
Improvements in neutron diffraction instrumentation are affording the opportunity to re-examine the structures of vertebrate hemoglobins and to interrogate proton and solvent position changes between the different quaternary states of the protein. For hemoglobins of unknown primary sequence, structural studies of cyanomethemoglobin (CNmetHb) are being used to help to resolve sequence ambiguity in the mass spectra. These studies have also provided additional structural evidence for the involvement of oxidized hemoglobin in the process of erythrocyte senescence. X-ray crystal studies of Tibetan snow leopard CNmetHb have shown that this protein crystallizes in the B state, a structure with a more open dyad, which possibly has relevance to RBC band 3 protein binding and erythrocyte senescence. R-state equine CNmetHb crystal studies elaborate the solvent differences in the switch and hinge region compared with a human deoxyhemoglobin T-state neutron structure. Lastly, comparison of histidine protonation between the T and R state should enumerate the Bohr-effect protons.
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Affiliation(s)
- Timothy C Mueser
- Department of Chemistry, University of Toledo, Toledo, OH 43606, USA.
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24
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Rapp J, Xu S, Sharp AM, Griffith WP, Kim YW, Funk MO. EPR spectroscopy and electrospray ionization mass spectrometry reveal distinctive features of the iron site in leukocyte 12-lipoxygenase. Arch Biochem Biophys 2009; 490:50-6. [PMID: 19683507 DOI: 10.1016/j.abb.2009.08.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [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: 06/27/2009] [Revised: 08/05/2009] [Accepted: 08/11/2009] [Indexed: 11/17/2022]
Abstract
The procedure for the expression and purification of recombinant porcine leukocyte 12-lipoxygenase using Escherichia coli [K.M. Richards, L.J. Marnett, Biochemistry 36 (1997) 6692-6699] was updated to make it possible to produce enough protein for physical measurements. Electrospray ionization tandem mass spectrometry confirmed the amino acid sequence. The redox properties of the cofactor iron site were examined by EPR spectroscopy at 25K following treatment with a variety of fatty acid hydroperoxides. Combination of the enzyme in a stoichiometric ratio with the hydroperoxides led to a g4.3 signal in EPR spectra instead of the g6 signal characteristic of similarly treated soybean lipoxygenase-1. Native 12-lipoxygenase was also subjected to electrospray ionization mass spectrometry. There was evidence for loss of the mass of an iron atom from the protein as the pH was lowered from 5 to 4. Native ions in these samples indicated that iron was lost without the protein completely unfolding.
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Affiliation(s)
- Johanna Rapp
- Department of Chemistry, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606, USA
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West EA, Griffith WP, Iphofen R. A historical perspective on the nursing shortage. Medsurg Nurs 2007; 16:124-30. [PMID: 17547272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Affiliation(s)
- Edith A West
- Indiana University of Pennsylvania, Indiana, PA, USA
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Abstract
Our previous studies of hemoglobin tetramer assembly in vitro suggested that the initial step in the oligomerization process, which ultimately dictates the high fidelity of the heterotetramer (alpha*beta*)2 assembly, is the binding of a flexible heme-free beta-globin chain to a highly ordered heme-bound alpha*-globin. In this work, we extend these studies to investigate formation of the homotetrameric hemoglobin H, whose formation in vivo is a well-documented clinical consequence of significant overexpression of beta-globin in alpha-thalassemic disorders. Upon reconstitution of the isolated beta-globin with excess heme, the predominant species in the ESI mass spectrum corresponds to the homotetramer beta*4, alongside homodimeric species and monomeric beta-globin chains in both apo and holo forms. The assembly process of the hemoglobin H homotetramer apparently follows a scenario similar to that of a normal heterodimeric hemoglobin (alpha*beta*)2 species, with the asymmetric binding event between compact and flexible polypeptide chains being the initial step. The extreme importance of large-scale chain dynamics and conformational heterogeneity for the protein assembly process is highlighted by the inability of highly structured alpha-globins to undergo ordered oligomerization to form dimers and tetramers as opposed to indiscriminate aggregation.
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Affiliation(s)
- Wendell P Griffith
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, USA
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Celic I, Masumoto H, Griffith WP, Meluh P, Cotter RJ, Boeke JD, Verreault A. The Sirtuins Hst3 and Hst4p Preserve Genome Integrity by Controlling Histone H3 Lysine 56 Deacetylation. Curr Biol 2006; 16:1280-9. [PMID: 16815704 DOI: 10.1016/j.cub.2006.06.023] [Citation(s) in RCA: 238] [Impact Index Per Article: 13.2] [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: 01/02/2006] [Revised: 05/06/2006] [Accepted: 06/07/2006] [Indexed: 11/20/2022]
Abstract
BACKGROUND Acetylation of histone H3 lysine 56 (K56Ac) occurs transiently in newly synthesized H3 during passage through S phase and is removed in G2. However, the physiologic roles and effectors of K56Ac turnover are unknown. RESULTS The sirtuins Hst3p and, to a lesser extent, Hst4p maintain low levels of K56Ac outside of S phase. In hst3 hst4 mutants, K56 hyperacetylation nears 100%. Residues corresponding to the nicotinamide binding pocket of Sir2p are essential for Hst3p function, and H3 K56 deacetylation is inhibited by nicotinamide in vivo. Rapid inactivation of Hst3/Hst4p prior to S phase elevates K56Ac to 50% in G2, suggesting that K56-acetylated nucleosomes are assembled genome-wide during replication. Inducible expression of Hst3p in G1 or G2 triggers deacetylation of mature chromatin. Cells lacking Hst3/Hst4p exhibit many phenotypes: spontaneous DNA damage, chromosome loss, thermosensitivity, and acute sensitivity to genotoxic agents. These phenotypes are suppressed by mutation of histone H3 K56 into a nonacetylatable residue or by loss of K56Ac in cells lacking the histone chaperone Asf1. CONCLUSIONS Our results underscore the critical importance of Hst3/Hst4p in controlling histone H3 K56Ac and thereby maintaining chromosome integrity.
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Affiliation(s)
- Ivana Celic
- High Throughput Biology Center, Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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Griffith WP, Kaltashov IA. Highly asymmetric interactions between globin chains during hemoglobin assembly revealed by electrospray ionization mass spectrometry. Biochemistry 2003; 42:10024-33. [PMID: 12924951 DOI: 10.1021/bi034035y] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.0] [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: 11/28/2022]
Abstract
Dynamics of bovine hemoglobin assembly was investigated by monitoring monomers/oligomers equilibria in solution with electrospray ionization mass spectrometry and circular dichroism spectroscopy. Intensities of ionic signals corresponding to various protein species (tetramers, dimers, heme-deficient dimers, as well as apo- and holo-monomers) were used to estimate relative fractions of these species in solution as a function of pH. The fraction of folded protein for each observed species was estimated based on charge-state distributions of corresponding ionic species in the mass spectra. The cumulative numbers (averaged across the entire protein population) were in good agreement with circular dichroism data at the Soret band and in the far-UV region, respectively. The mass spectral data confirm that hemoglobin dissociation involves a step where heme is first lost from the beta-chain of the alpha beta-dimer to form a heme-deficient dimeric species. This dimer dissociates further to produce a holo-alpha-chain and an apo-beta-chain. The former is tightly folded into a comparatively compact structure at neutral pH, while the latter always exhibits significant backbone disorder. Acidification of the protein solution to pH 4 leads to partial heme dissociation and significant increase of the backbone flexibility in the alpha-chains as well. Complete dissociation of the heme from the alpha-chains at a pH below 4 coincides with the total disappearance of the dimeric and tetrameric hemoglobin species from the mass spectra. The experimental data provide strong evidence that binding of a partially unstructured apo-beta-chain to a tightly folded holo-alpha-chain to form a heme-deficient dimer is the initial step of hemoglobin assembly. Such binding locks the beta-chain in a highly ordered conformation, which allows for an efficient heme acquisition, followed by docking of two hemoglobin dimers to form a tetrameric form of the protein. The asymmetry of the roles of the two chains in the assembly process is surprising, given a rather high sequence homology (ca. 43%) and highlights functional importance of intrinsic protein disorder. The study also demonstrates a tremendous potential of mass spectrometry as an analytical tool capable of elucidating protein interaction mechanisms in highly heterogeneous systems.
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Affiliation(s)
- Wendell P Griffith
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, USA
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Griffith WP. Priestley in London. Notes Rec R Soc Lond 1983; 38:1-16. [PMID: 11615942 DOI: 10.1098/rsnr.1983.0001] [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: 05/23/2023]
Abstract
Joseph Priestley was more a visitor to London than a resident, though I he spent three troubled years in Hackney after the riots of 1791 had destroyed his house, laboratory and chapels in Birmingham. Nevertheless, his annual visits from 1766 to the Royal Society, to clubs and coffee houses, to Unitarian chapels and the homes of his many friends in London provided much of the stimulus for his scientific, religious and political thought. Although there are now only a few visible reminders of his visits to London, it is still possible to trace some of the places at which he stayed or preached, and it is the aim of this paper to identify these and to provide a brief picture of Priestley’s London life. There seems to have been only one previous publication related to this topic, a note which deals more with the London life of his associates than of Priestley himself. This account is prefaced by a short summary of his life; there are a number of biographies of Priestley (2).
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Carrondo MA, Griffith WP, Hall JP, Skapski AC. X-ray structure of [Ru3 O2 (NH3)14]6+, cation of the cytological reagent Ruthenium Red. Biochim Biophys Acta 1980; 627:332-4. [PMID: 6153278 DOI: 10.1016/0304-4165(80)90464-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The X-ray crystal structure of [Ru3 O2 (NH3)14] (S2 O3)3 . 4H2 O, the thiosulphate salt of Ruthenium Red, has been determined. The cation contains an essentially linear N-Ru-O-Ru-O-Ru-N backbone formed from three ruthenium coordination octahedra, giving an effectively cylindrical shape to the ion. Resonance Raman spectra are consistent with retention of this structure in solution.
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Abstract
The osmiophilia, under the conditions of normal tissue fixation, of the histidine, lysine, tryptophan, cysteine and methionine side chain of proteins is suggested by in vitro studies on blocked amino acids representative of such protein side chains, and the chemical nature of the reaction products elucidated. The chemical feasibility of inter- or intramolecular cross-linking of protein by OsO4 at these and other sites is demonstrated, as in the cross-linking of protein with unsaturated lipids such as methyl oleate, methyl linoleate and linolenate, and cholesteryl acetate. The relevance of these results to the process of tissue fixation by OsO4 is discussed.
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Abstract
It has been postulated that phenol-containing areas of plant and animal tissues were osmiophilic, but proof of direct interaction between osmium tetroxide and phenolic materials, or the nature of such reactions, has been lacking. We find that, under conditions similar to those of normal tissue fixation, osmium tetroxide reacts rapidly with those phenols containing o-dihydroxy groups (including such species found in plant tissues) to give very stable chelate complexes. We conclude that these complexes are responsible for the observed electron-density in phenol-containing areas of tissue treated with osmium tetroxide, so that such phenols are indeed osmiophilic.
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Collin R, Griffith WP, Phillips FL, Skapski AC. Staining and fixation of unsaturated membrane lipids by osmium tetroxide. Crystal structure of a model osmium(VI) di-ester. Biochim Biophys Acta 1974; 354:152-4. [PMID: 4136208 DOI: 10.1016/0304-4165(74)90064-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Collin R, Griffith WP, Phillips FL, Skapski AC. Staining and fixation of unsaturated membrane lipids by osmium tetroxide: crystal structure of a model osmium(VI) intermediate. Biochim Biophys Acta 1973; 320:745-7. [PMID: 4127530 DOI: 10.1016/0304-4165(73)90157-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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