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Marts AR, Kaine JC, Baum RR, Clayton VL, Bennett JR, Cordonnier LJ, McCarrick R, Hasheminasab A, Crandall LA, Ziegler CJ, Tierney DL. Paramagnetic Resonance of Cobalt(II) Trispyrazolylmethanes and Counterion Association. Inorg Chem 2016; 56:618-626. [PMID: 27977149 DOI: 10.1021/acs.inorgchem.6b02520] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [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
Paramagnetic resonance studies (EPR, ESEEM, ENDOR, and NMR) of a series of cobalt(II) bis-trispyrazolylmethane tetrafluoroborates are presented. The complexes studied include the parent, unsubstituted ligand (Tpm), two pyrazole-substituted derivatives (4Me and 3,5-diMe), and tris(1-pyrazolyl)ethane (Tpe), which includes a methyl group on the apical carbon atom. NMR and ENDOR establish the magnitude of 1H hyperfine couplings, while ESEEM provides information on the coordinated 14N. The data show that the pyrazole 3-position is more electron rich in the Tpm analogues, that the geometry about the apical atom influences the magnetic resonance, and that apical atom geometry appears more fixed in Tpm than in Tp. NMR and ENDOR establish that the BF4- counterion remains associated in fluid solution. In the case of the Tpm3,5Me complex, it appears to associate in solution, in the same position it occupies in the X-ray structure.
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Affiliation(s)
- Amy R Marts
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Joshua C Kaine
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Robert R Baum
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Vivien L Clayton
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Jami R Bennett
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Laura J Cordonnier
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Robert McCarrick
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
| | - Abed Hasheminasab
- Department of Chemistry, University of Akron , Akron, Ohio 44325, United States
| | - Laura A Crandall
- Department of Chemistry, University of Akron , Akron, Ohio 44325, United States
| | | | - David L Tierney
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
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Aitha M, Moritz L, Sahu ID, Sanyurah O, Roche Z, McCarrick R, Lorigan GA, Bennett B, Crowder MW. Conformational dynamics of metallo-β-lactamase CcrA during catalysis investigated by using DEER spectroscopy. J Biol Inorg Chem 2015; 20:585-94. [PMID: 25827593 PMCID: PMC4733638 DOI: 10.1007/s00775-015-1244-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [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: 09/10/2014] [Accepted: 01/26/2015] [Indexed: 10/24/2022]
Abstract
Previous crystallographic and mutagenesis studies have implicated the role of a position-conserved hairpin loop in the metallo-β-lactamases in substrate binding and catalysis. In an effort to probe the motion of that loop during catalysis, rapid-freeze-quench double electron-electron resonance (RFQ-DEER) spectroscopy was used to interrogate metallo-β-lactamase CcrA, which had a spin label at position 49 on the loop and spin labels (at positions 82, 126, or 233) 20-35 Å away from residue 49, during catalysis. At 10 ms after mixing, the DEER spectra show distance increases of 7, 10, and 13 Å between the spin label at position 49 and the spin labels at positions 82, 126, and 233, respectively. In contrast to previous hypotheses, these data suggest that the loop moves nearly 10 Å away from the metal center during catalysis and that the loop does not clamp down on the substrate during catalysis. This study demonstrates that loop motion during catalysis can be interrogated on the millisecond time scale.
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Affiliation(s)
- Mahesh Aitha
- Department of Chemistry and Biochemistry, Miami University, 650 East High Street, Oxford, Ohio 45056, USA
| | - Lindsay Moritz
- Department of Chemistry and Biochemistry, Miami University, 650 East High Street, Oxford, Ohio 45056, USA
| | - Indra D. Sahu
- Department of Chemistry and Biochemistry, Miami University, 650 East High Street, Oxford, Ohio 45056, USA
| | - Omar Sanyurah
- Department of Chemistry and Biochemistry, Miami University, 650 East High Street, Oxford, Ohio 45056, USA
| | - Zahilyn Roche
- Department of Chemistry and Biochemistry, Miami University, 650 East High Street, Oxford, Ohio 45056, USA
| | - Robert McCarrick
- Department of Chemistry and Biochemistry, Miami University, 650 East High Street, Oxford, Ohio 45056, USA
| | - Gary A. Lorigan
- Department of Chemistry and Biochemistry, Miami University, 650 East High Street, Oxford, Ohio 45056, USA
| | - Brian Bennett
- Physics Department, Marquette University, 540 N. 15th Street, Milwaukee, Wisconsin 53233, USA, and Department of Biophysics, Medical College of Wisconsin, 8701 W. Watertown Plank Road, Milwaukee, Wisconsin 53226, USA
| | - Michael W. Crowder
- Department of Chemistry and Biochemistry, Miami University, 650 East High Street, Oxford, Ohio 45056, USA
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Aitha M, Richmond TK, Hu Z, Hetrick A, Reese R, Gunther A, McCarrick R, Bennett B, Crowder MW. Dilution of dipolar interactions in a spin-labeled, multimeric metalloenzyme for DEER studies. J Inorg Biochem 2014; 136:40-6. [PMID: 24742748 PMCID: PMC4733626 DOI: 10.1016/j.jinorgbio.2014.03.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [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: 12/31/2013] [Revised: 03/17/2014] [Accepted: 03/18/2014] [Indexed: 01/28/2023]
Abstract
The metallo-β-lactamases (MβLs), which require one or two Zn(II) ions in their active sites for activity, hydrolyze the amide bond in β-lactam-containing antibiotics, and render the antibiotics inactive. All known MβLs contain a mobile element near their active sites, and these mobile elements have been implicated in the catalytic mechanisms of these enzymes. However little is known about the dynamics of these elements. In this study, we prepared a site-specific, double spin-labeled analog of homotetrameric MβL L1 with spin labels at positions 163 and 286 and analyzed the sample with DEER (double electron electron resonance) spectroscopy. Four unique distances were observed in the DEER distance distribution, and these distances were assigned to the desired intramolecular dipolar coupling (between spin labels at positions 163 and 286 in one subunit) and to intermolecular dipolar couplings. To rid the spin-labeled analog of L1 of the intermolecular couplings, spin-labeled L1 was "diluted" by unfolding/refolding the spin-labeled enzyme in the presence of excess wild-type L1. DEER spectra of the resulting, spin-diluted enzyme revealed a single distance corresponding to the desire intramolecular dipolar coupling.
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Affiliation(s)
- Mahesh Aitha
- Department of Chemistry and Biochemistry, Miami University, 160 Hughes Hall, Oxford, OH 45056, United States
| | - Timothy K Richmond
- Department of Chemistry and Biochemistry, Miami University, 160 Hughes Hall, Oxford, OH 45056, United States
| | - Zhenxin Hu
- Department of Chemistry and Biochemistry, Miami University, 160 Hughes Hall, Oxford, OH 45056, United States
| | - Alyssa Hetrick
- Department of Chemistry and Biochemistry, Miami University, 160 Hughes Hall, Oxford, OH 45056, United States
| | - Raquel Reese
- Department of Chemistry and Biochemistry, Miami University, 160 Hughes Hall, Oxford, OH 45056, United States
| | - Althea Gunther
- Department of Chemistry and Biochemistry, Miami University, 160 Hughes Hall, Oxford, OH 45056, United States
| | - Robert McCarrick
- Department of Chemistry and Biochemistry, Miami University, 160 Hughes Hall, Oxford, OH 45056, United States
| | - Brian Bennett
- Department of Biophysics, National Biomedical EPR Center, Medical College of Wisconsin, Milwaukee, WI 53226, United States
| | - Michael W Crowder
- Department of Chemistry and Biochemistry, Miami University, 160 Hughes Hall, Oxford, OH 45056, United States.
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Bottorf LM, Liu L, Sahu ID, McCarrick R, Lorigan GA. Probing the Structural Topology of a Membrane Peptide in Mechcanically Aligned Lipid Bilayers using Bifunctional Spin Labeling EPR Spectroscopy. Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.1134] [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: 10/23/2022] Open
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Ghimire H, Hustedt EJ, Sahu ID, Inbaraj JJ, McCarrick R, Mayo DJ, Benedikt MR, Lee RT, Grosser SM, Lorigan GA. Distance measurements on a dual-labeled TOAC AChR M2δ peptide in mechanically aligned DMPC bilayers via dipolar broadening CW-EPR spectroscopy. J Phys Chem B 2012; 116:3866-73. [PMID: 22379959 DOI: 10.1021/jp212272d] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [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
A membrane alignment technique has been used to measure the distance between two TOAC nitroxide spin labels on the membrane-spanning M2δ, peptide of the nicotinic acetylcholine receptor (AChR), via CW-EPR spectroscopy. The TOAC-labeled M2δ peptides were mechanically aligned using DMPC lipids on a planar quartz support, and CW-EPR spectra were recorded at specific orientations. Global analysis in combination with rigorous spectral simulation was used to simultaneously analyze data from two different sample orientations for both single- and double-labeled peptides. We measured an internitroxide distance of 14.6 Å from a dual TOAC-labeled AChR M2δ peptide at positions 7 and 13 that closely matches with the 14.5 Å distance obtained from a model of the labeled AChR M2δ peptide. In addition, the angles determining the relative orientation of the two nitroxides have been determined, and the results compare favorably with molecular modeling. The global analysis of the data from the aligned samples gives much more precise estimates of the parameters defining the geometry of the two labels than can be obtained from a randomly dispersed sample.
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Affiliation(s)
- Harishchandra Ghimire
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, United States
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Liu L, Mayo D, Sahu I, McCarrick R, Troxel K, Lorigan G. Probing the Secondary Structure of Membrane Proteins with the Pulsed EPR ESSEM Technique. Biophys J 2012. [DOI: 10.1016/j.bpj.2011.11.1469] [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: 10/14/2022] Open
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Mayo D, Zhou A, Sahu I, McCarrick R, Walton P, Ring A, Troxel K, Coey A, Hawn J, Emwas AH, Lorigan GA. Probing the structure of membrane proteins with electron spin echo envelope modulation spectroscopy. Protein Sci 2011; 20:1100-4. [PMID: 21563228 DOI: 10.1002/pro.656] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 04/26/2011] [Accepted: 05/03/2011] [Indexed: 11/09/2022]
Abstract
A new approach has been developed to probe the structural properties of membrane peptides and proteins using the pulsed electron paramagnetic resonance technique of electron spin echo envelope modulation (ESEEM) spectroscopy and the α-helical M2δ subunit of the acetylcholine receptor incorporated into phospholipid bicelles. To demonstrate the practicality of this method, a cysteine-mutated nitroxide spin label (SL) is positioned 1, 2, 3, and 4 residues away from a fully deuterated Val side chain (denoted i + 1 to i + 4). The characteristic periodicity of the α-helical structure gives rise to a unique pattern in the ESEEM spectra. In the i + 1 and i + 2 samples, the ²H nuclei are too far away to be detected. However, with the 3.6 residue per turn pattern of an α-helix, the i + 3 and i + 4 samples reveal a strong signal from the ²H nuclei of the Val side chain. Modeling studies verify these data suggesting that the closest ²H-labeled Val to SL distance would in fact be expected in the i + 3 and i + 4 samples. This technique is very advantageous, because it provides pertinent qualitative structural information on an inherently difficult system like membrane proteins in a short period of time (minutes) with small amounts of protein (μg).
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Affiliation(s)
- Daniel Mayo
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio, USA
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Kuntzleman T, McCarrick R, Penner-Hahn J, Yocum C. Probing reactive sites within the Photosystem II manganese cluster: Evidence for separate populations of manganese that differ in redox potential. Phys Chem Chem Phys 2004. [DOI: 10.1039/b406601d] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Markland W, Petrillo RA, Fitzgibbon M, Fox T, McCarrick R, McQuaid T, Fulghum JR, Chen W, Fleming MA, Thomson JA, Chambers SP. Purification and characterization of the NS3 serine protease domain of hepatitis C virus expressed in Saccharomyces cerevisiae. J Gen Virol 1997; 78 ( Pt 1):39-43. [PMID: 9010283 DOI: 10.1099/0022-1317-78-1-39] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
cDNA encoding the putative core of the hepatitis C virus NS3 serine protease domain (residues 1-181 of NS3; NS3 (181)) was expressed as an N-terminally (His)6-tagged fusion protein in Saccharomyces cerevisiae. NS3 (181) protease activity was found in soluble cell lysates, and the N-terminal metal-chelating domain facilitated the efficient purification of active enzyme, using immobilized metal affinity chromatography. The purified NS3(181), protease activity was characterized by assaying the trans-cleavage of in vitro transcription-translation generated substrates, and subsequently a previously unobserved cleavage site within the NS5A region was identified. The inhibitory effect of known protease inhibitors was also examined. It is hoped that availability of this method for the expression and purification of the NS3(181) protease will facilitate the development of anti-hepatitis C therapies.
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Affiliation(s)
- W Markland
- Vertex Pharmaceuticals Inc., Cambridge, MA 02139-4242, USA
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