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Gabel SA, Smith CE, Cuneo MJ, Mueller GA, Kirby TW, DeRose EF, Krahn JM, London RE. Characterization of the redox transition of the XRCC1 N-terminal domain. Structure 2014; 22:1754-1763. [PMID: 25456813 DOI: 10.1016/j.str.2014.09.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 08/11/2014] [Accepted: 09/05/2014] [Indexed: 10/24/2022]
Abstract
XRCC1, a scaffold protein involved in DNA repair, contains an N-terminal domain (X1NTD) that interacts specifically with DNA polymerase β. It was recently discovered that X1NTD contains a disulfide switch that allows it to adopt either of two metamorphic structures. In the present study, we demonstrate that formation of an N-terminal proline carbimate adduct resulting from the nonenzymatic reaction of Pro2 with CO2 is essential for stabilizing the oxidized structure, X1NTDox. The kinetic response of X1NTDred to H2O2, monitored by NMR, was determined to be very slow, consistent with involvement of the buried, kinetically trapped Cys12 residue, but was significantly accelerated by addition of protein disulfide isomerase or by Cu(2+). NMR analysis of a sample containing the pol β polymerase domain, and both the reduced and oxidized forms of X1NTD, indicates that the oxidized form binds to the enzyme 25-fold more tightly than the reduced form.
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Affiliation(s)
- Scott A Gabel
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Cassandra E Smith
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Matthew J Cuneo
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Geoffrey A Mueller
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Thomas W Kirby
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Eugene F DeRose
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Juno M Krahn
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA
| | - Robert E London
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC 27709, USA.
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Aoyagi N, Furusho Y, Sei Y, Endo T. Fast equilibrium of zwitterionic adduct formation in reversible fixation–release system of CO2 by amidines under dry conditions. Tetrahedron 2013. [DOI: 10.1016/j.tet.2013.04.110] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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3
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Terrier P, Douglas DJ. Carbamino group formation with peptides and proteins studied by mass spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2010; 21:1500-5. [PMID: 20580570 DOI: 10.1016/j.jasms.2010.05.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Revised: 05/21/2010] [Accepted: 05/22/2010] [Indexed: 05/15/2023]
Abstract
At high pH and in the presence of dissolved CO(2), the N-terminus and epsilon-amino groups of amino acids, peptides, and proteins can form carbamino adducts with CO(2), R-NH(2) + CO(2) <--> R-NHCOO(-) + H(+). We report the first study of carbamino group formation by electrospray ionization (ESI) mass spectrometry (MS). Angiotensin II, bradykinin, substance P, and insulin have been studied. A careful optimization of the instrumental parameters was necessary to allow the transfer of the fragile adducts into vacuum for mass analysis. Particularly, dissociation of the adducts in the ion sampling process and pH changes in ESI must be minimized. With these precautions, levels of carbamino group formation of angiotensin II and bradykinin determined from mass spectra agree with those expected to be in solution, calculated from literature equilibrium constants. Thus, ESI MS can quantitatively measure ratios of carbamino adduct to total peptide concentration in solution. Values of equilibrium constants for carbamino group formation with substance P (pK(c) = 4.77 +/- 0.18) and insulin (pK(c) = 4.99 +/- 0.05) are reported for the first time.
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Affiliation(s)
- Peran Terrier
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
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4
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Villiers C, Dognon JP, Pollet R, Thuéry P, Ephritikhine M. An isolated CO2 adduct of a nitrogen base: crystal and electronic structures. Angew Chem Int Ed Engl 2010; 49:3465-8. [PMID: 20358577 DOI: 10.1002/anie.201001035] [Citation(s) in RCA: 160] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Claude Villiers
- CEA Saclay, DSM, IRAMIS, UMR 3299 CEA/CNRS SIS2M, 91191 Gif-sur-Yvette cedex, France.
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5
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Villiers C, Dognon JP, Pollet R, Thuéry P, Ephritikhine M. An Isolated CO2Adduct of a Nitrogen Base: Crystal and Electronic Structures. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201001035] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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6
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Reisner HM, Lundblad RL. Identifying residues in antigenic determinants by chemical modification. Methods Mol Biol 2009; 524:103-117. [PMID: 19377940 DOI: 10.1007/978-1-59745-450-6_8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Chemical modification of the side chains of amino acid residues was one of the first methods developed to investigate epitopes in protein antigens. The principle of the method is that alteration of the structure of a key residue of an epitope by a chemical modification will alter reactivity with antibody by affecting either specificity or avidity or both. Chemical modification has the advantage that it can be applied to discontinuous as well as continuous epitopes and may be of value in identifying cryptic epitopes. We consider here the several recent studies that have applied site-specific chemical modification to the identification of epitopes on antigens, including the use of formaldehyde, glutaraldehyde, and acid anhydrides, to produce allergoids where determinants important to reaction with IgE are modified but the ability to elicit an IgG response is retained. It is noteworthy that modification of amino groups with charge reversal appears to be the most useful approach. The approach to the use of site-specific chemical modification as a tool for the study of protein function is discussed, and emphasis is placed on the necessity to (1) validate the specificity of modification and (2) assess potential conformational change that may occur secondary to modification. Finally, a list of chemical reagents used for protein modification is presented, together with properties and references to use.
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Affiliation(s)
- Howard M Reisner
- Department of Pathology and Laboratory Medicine, University of North Carolina, PO Box 16695, Chapel Hill, NC 27516, USA
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Morollo AA, Petsko GA, Ringe D. Structure of a Michaelis complex analogue: propionate binds in the substrate carboxylate site of alanine racemase. Biochemistry 1999; 38:3293-301. [PMID: 10079072 DOI: 10.1021/bi9822729] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The structure of alanine racemase from Bacillus stearothermophilus with the inhibitor propionate bound in the active site was determined by X-ray crystallography to a resolution of 1.9 A. The enzyme is a homodimer in solution and crystallizes with a dimer in the asymmetric unit. Both active sites contain a pyridoxal 5'-phosphate (PLP) molecule in aldimine linkage to Lys39 as a protonated Schiff base, and the pH-independence of UV-visible absorption spectra suggests that the protonated PLP-Lys39 Schiff base is the reactive form of the enzyme. The carboxylate group of propionate bound in the active site makes numerous interactions with active-site residues, defining the substrate binding site of the enzyme. The propionate-bound structure therefore approximates features of the Michaelis complex formed between alanine racemase and its amino acid substrate. The structure also provides evidence for the existence of a carbamate formed on the side-chain amino group of Lys129, stabilized by interactions with one of the residues interacting with the carboxylate group of propionate, Arg136. We propose that this novel interaction influences both substrate binding and catalysis by precisely positioning Arg136 and modulating its charge.
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Affiliation(s)
- A A Morollo
- Department of Biochemistry, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02254, USA
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Neuroactive carbamate adducts of beta-N-methylamino-L-alanine and ethylenediamine. Detection and quantitation under physiological conditions by 13C NMR. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(18)86928-9] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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