Eric Walter

Eric Walter
Staff Member Title: 
Senior Research Scientist
Phone: 
(509) 371-6873
Contact Email: 
Eric.Walter@pnnl.gov
Overview: 

Dr. Walter is the user contact for Electron Paramagnetic Resonance (EPR). He assists EMSL users in applying both X-Band and W-Band pulsed EPR spectroscopy to diverse fields, such as geochemistry, catalysis, metalloproteins, and solid-state physics.

Details: 
  • 2004-2009, Post-doctoral researcher, University of California, Santa Cruz (UCSC)
  • Past Projects Prion Protein and Copper While a post-doctoral researcher at UCSC in the lab of Glenn Millhauser, Dr. Walter developed several techniques for investigations of metalloproteins. Using solid-phase peptide synthesis and EPR, he was able to show that the natively unstructured octarepeat region of the prion protein used a series of different binding modes for copper, depending on the copper-to-protein ratio. He then developed a competition method for determining the affinity of each of these binding modes for copper. These results showed that the prion protein actually binds copper with negative cooperativity, not the positive cooperativity that had been previously reported. These techniques have been expanded to other metals (zinc) and proteins (-synuclein).
Education: 
  • Ph.D., Chemistry, Montana State University, Bozeman, Montana, 2004
  • B.S., Chemistry, University of Delaware, Newark, Delaware, 1996
Research Interests: 

Affinity and Dynamics of Tethered Biomolecules Dr. Walter has developed a unique, continuous flow technique for determining the affinity of biomolecules for ligands. By tethering the biomolecule to a solid-phase (usually chromatography media), a column the dimensions of a typical EPR sample can be created. When placed in the EPR spectrometer, a continuous flow of ligand can be passed over the sample and the binding monitored in real time. This technique currently is being adapted to catalytic materials and a gas mobile phase. Structure and theory of the Photosystem II Oxygen Evolving Center (OEC) In collaboration with Ping Yang, Andrew Lipton, and K.V. Lakshmi, Dr. Walter is investigating the structure of the OEC, using a combination of magnetic resonance spectroscopy, cryogenic NMR, high-field EPR, and theoretical structure prediction. The research also involves using the theoretical prediction of magnetic resonance parameters in conjunction with the structure of known model compounds to refine experimental results.

Capabilities: 
NMR and EPR
Instrument(s): 
High Field W-Band (95 GHz) EPR

Publications

2016

  • PN Reardon, SS Chacon, ED Walter, ME Bowden, NM Washton, MW Kleber. 2016. "Abiotic protein fragmentation by manganese oxide: implications for a mechanism to supply soil biota with oligopeptides." Environmental Science & Technology 50(7)3486–3493. 10.1021/acs.est.5b04622
  • F Gao, Y Zheng, RK Kukkadapu, Y Wang, ED Walter, B Schwenzer, J Szanyi, CHF Peden. 2016. "Iron loading effects in Fe/SSZ-13 NH3-SCR catalysts: nature of the Fe-ions and structure-function relationships ." ACS Catalysis 6(5)2939-2954. 10.1021/acscatal.6b00647
  • Q Huang, ED Walter, L Cosimbescu, D Choi, JP Lemmon. 2016. "In situ electrochemical-electron spin resonance investigations of multi-electron redox reaction for organic radical cathodes." Journal of Power Sources 306812-816. 10.1016/j.jpowsour.2015.11.080
  • TG Levitskaia, S Chatterjee, N Pence, J Romero, T Varga, MH Engelhard, Y Du, L Kovarik, BW Arey, ME Bowden, ED Walter. 2016. "Inorganic Tin Aluminophosphate Nanocomposite for Reductive Separation of Pertechnetate." Environmental Science: Nano 3(2)1003-1013. 10.1039/C6EN00130K

2015

  • J Chen, D Wu, ED Walter, MH Engelhard, P Bhattacharya, H Pan, Y Shao, F Gao, J Xiao, J Liu. 2015. "Molecular-Confinement of Polysulfide within Mesoscale Electrodes for the Practical Application of Lithium Sulfur Batteries." Nano Energy 13267-274. 10.1016/j.nanoen.2015.01.031
  • J Xiao, JZ Hu, H Chen, M Vijayakumar, J Zheng, H Pan, ED Walter, MY Hu, X Deng, J Feng, BY Liaw, M Gu, Z Deng, D Lu, S Xu, CM Wang, J Liu. 2015. "Following the Transient Reactions in Lithium-Sulfur Batteries Using In an In Situ Nuclear Magnetic Resonance Technique." Nano Letters 15(5)3309-3316. 10.1021/acs.nanolett.5b00521
  • M Vijayakumar, Z Nie, ED Walter, JZ Hu, J Liu, VL Sprenkle, W Wang. 2015. "Understanding Aqueous Electrolyte Stability through Combined Computational and Magnetic Resonance Spectroscopy: A Case Study on Vanadium Redox Flow Battery Electrolytes." ChemPlusChem 80(2)428-437. 10.1002/cplu.201402139
  • X Wei, W Xu, J Huang, L Zhang, ED Walter, CW Lawrence, M Vijayakumar, WA Henderson, TL. Liu, L Cosimbescu, B Li, VL Sprenkle, W Wang. 2015. "Radical Compatibility with Nonaqueous Electrolytes and Its Impact on an All-Organic Redox Flow Battery." Angewandte Chemie International Edition 127(30)8808-8811. 10.1002/ange.201501443
  • F Gao, ED Walter, NM Washton, J Szanyi, CHF Peden. 2015. "Synthesis and Evaluation of Cu/SAPO-34 Catalysts for NH3-SCR 2: Solid-state Ion Exchange and One-pot Synthesis." Applied Catalysis. B, Environmental 162501-514. 10.1016/j.apcatb.2014.07.029
  • Q Wang, J Zheng, ED Walter, H Pan, D Lu, P Zuo, H Chen, Z Deng, BY Liaw, X Yu, X Yang, J Zhang, J Liu, J Xiao. 2015. "Direct Observation of Sulfur Radicals as Reaction Media in lithium Sulfur Batteries." Journal of the Electrochemical Society 162(3)A474-A478. 10.1149/2.0851503jes
  • MD Mccluskey, C Corolewski, J Lv, MC Tarun, ST Teklemichael, ED Walter, MG Norton, KW Harrison, SY Ha. 2015. "Acceptors in ZnO." Journal of Applied Physics 117(11)Article No. 112802. 10.1063/1.4913827
  • WZ Li, F Gao, Y Li, ED Walter, J Liu, CHF Peden, Y Wang. 2015. "Nanocrystalline Anatase Titania Supported Vanadia Catalysts: Facet-dependent Structure of Vanadia." Journal of Physical Chemistry C 119(27)15094−15102. 10.1021/acs.jpcc.5b01486
  • S Xu, ED Walter, Z Zhao, MY Hu, X Han, JZ Hu, X Bao. 2015. "Dynamic Structural Changes of SiO2 Supported Pt−Ni Bimetallic Catalysts over Redox Treatments Revealed by NMR and EPR." Journal of Physical Chemistry C 119(36)21219-21226. 10.1021/acs.jpcc.5b06344

2014

  • R Cao, ED Walter, W Xu, EN Nasybulin, P Bhattacharya, ME Bowden, MH Engelhard, J Zhang. 2014. "The Mechanisms of Oxygen Reduction and Evolution Reactions in Nonaqueous Lithium-Oxygen Batteries." ChemSusChem 7(9)2436-2440. 10.1002/cssc.201402315
  • M Vijayakumar, N Govind, ED Walter, SD Burton, AK Shukla, A Devaraj, J Xiao, J Liu, CM Wang, AM Karim, S Thevuthasan. 2014. "Molecular Structure and Stability of Dissolved Lithium Polysulfide Species." Physical Chemistry Chemical Physics. PCCP 16(22)10923-10932. 10.1039/c4cp00889H
  • MJ Wilkins, DW Hoyt, MJ Marshall, PA Alderson, AE Plymale, LMeng Markillie, AE Tucker, ED Walter, BE Linggi, A Dohnalkova, RC Taylor. 2014. "CO2 exposure at pressure impacts metabolism and stress responses in the model sulfate-reducing bacterium Desulfovibrio vulgaris strain Hildenborough." Frontiers in Microbiology 5Article No. 507. 10.3389/fmicb.2014.00507
  • F Gao, ED Walter, M Kollar, Y Wang, J Szanyi, CHF Peden. 2014. "Understanding ammonia selective catalytic reduction kinetics over Cu-SSZ-13 from motion of the Cu ions." Journal of Catalysis 3191-14. 10.1016/j.jcat.2014.08.010
  • ZM Heiden, S Chen, LAN Labios, RMorris Bullock, ED Walter, EL Tyson, MT Mock. 2014. "Proton and Electron Additions to Iron (II) Dinitrogen Complexes Containing Pendant Amines." Organometallics 33(6)1333-1336. 10.1021/om401089d

2013

  • F Gao, ED Walter, EM Karp, JY Luo, RG Tonkyn, JH Kwak, J Szanyi, CHF Peden. 2013. "Structure-Activity Relationships in NH3-SCR over Cu-SSZ-13 as Probed by Reaction Kinetics and EPR Studies." Journal of Catalysis 300(1)20-29. 10.1016/j.jcat.2012.12.020
  • F Gao, ED Walter, NM Washton, J Szanyi, CHF Peden. 2013. "Synthesis and Evaluation of Cu-SAPO-34 Catalysts for Ammonia Selective Catalytic Reduction. 1. Aqueous Solution Ion Exchange." ACS Catalysis 3(9)2083-2093. 10.1021/cs4004672
  • CG Dudzik, ED Walter, BS Abrams, MS Jurica, GL Millhauser. 2013. "Coordination of Copper to the Membrane-Bound Form of α-Synuclein." Biochemistry 52(1)53-60. 10.1021/bi301475q
  • A Raitsimring, AV Astashkin, JH Enemark, I Kaminker, D Goldfarb, ED Walter, Y Song, TJ Meade. 2013. "Optimization of pulsed-DEER measurements for Gd-based labels: choice of operational frequencies, pulse durations and positions, and temperature." Applied Magnetic Resonance 44(6)649-670. 10.1007/s00723-012-0434-6
  • EF van der Eide, ML Helm, ED Walter, RMorris Bullock. 2013. "Structural and Spectroscopic Characterization of 17- and 18-Electron Piano-Stool Complexes of Chromium. Thermochemical Analyses of Weak Cr-H Bonds." Inorganic Chemistry 52(3)1591-1603. 10.1021/ic302460y

2012

  • SK Sundaram, JS McCloy, BJ Riley, MK Murphy, HA Qiao, CF Windisch, ED Walter, JV Crum, R Golovchak, O Shpotyuk. 2012. "Gamma Radiation Effects on Physical, Optical, and Structural Properties of Binary As-S glasses." Journal of the American Ceramic Society 95(3)1048-1055. 10.1111/j.1551-2916.2011.04938.x
  • EF van der Eide, TL. Liu, DM Camaioni, ED Walter, RMorris Bullock. 2012. "Facile Thermal W-W Bond Homolysis in the N-Heterocyclic Carbene-Containing Tungsten Dimer [CpW(CO)2(IMe)]2." Organometallics 31(5)1775-1789. 10.1021/om201162g
  • DR Ferreira, CP Schulthess, JE Amonette, ED Walter. 2012. "An electron paramagnetic resonance spectroscopy investigation of the retention mechanisms of Mn and Cu in the nanopore channels of three zeolite minerals." Clays and Clay Minerals 60(6)588-598. 10.1346/CCMN.2012.0600604
  • EF van der Eide, P Yang, ED Walter, TL. Liu, RMorris Bullock. 2012. "Dinuclear Metalloradicals Featuring Unsupported Metal-Metal Bonds." Angewandte Chemie International Edition 51(33)8361-8364. 10.1002/anie.201203531

2011

  • ST Teklemichael, WMH Oo, MC Matthew, ED Walter, DW Hoyt. 2011. "Acceptors in ZnO nanocrystals." Applied Physics Letters 98(23)Article No. 232112. 10.1063/1.3598411
  • JA Roberts, JA Franz, EF van der Eide, ED Walter, JL Petersen, DL DuBois, RMorris Bullock. 2011. "Comproportionation of Cationic and Anionic Tungsten Complexes Having an N-Heterocyclic Carbene Ligand to Give the Isolable 17-Electron Tungsten Radical, CpW(CO)2(IMes)• ." Journal of the American Chemical Society 133(37)14593-14603. 10.1021/ja202754e