This subproject is one of many research subprojects utilizing theresources provided by a Center grant funded by NIH/NCRR. The subproject andinvestigator (PI) may have received primary funding from another NIH source,and thus could be represented in other CRISP entries. The institution listed isfor the Center, which is not necessarily the institution for the investigator.The research seeks to use x-ray absorption spectroscopy, in combination with Mossbauer spectroscopy, to determine (as a function of pH) the protonation state of a number of high-valent iron(IV)oxo, or ferryl, intermediates found in oxidative heme-proteins. The importance of this work lies in the observation that the ability of metal-oxos to abstract hydrogen scales with the strength of the O-H bond formed during H-atom abstraction. In oxidative heme-enzymes the strength of this O-H bond depends upon the one electron reduction potential of compound I (a ferryl-radical species) and the pKa of the ferryl species, called compound II. Only thiolate-ligated heme enzymes are known to insert oxygen into C-H bonds. This reaction is thought to occur through a mechanism that involves hydrogen abstraction. Recently one of us (MTG) performed EXAFS measurements on a ferryl form of chloroperoxidase (a thiolate-ligated heme-enzyme known to hydroxylate activated C-H bonds) and found that this intermediate was basic (pKa ~ 8.2). This finding suggests that Nature may be using thiolate-ligation to promote hydrogen abstraction rather than the one-electron oxidations performed by histidine-ligated heme-enzymes. The experiments outlined in this proposal aim to examine this hypothesis. They seek to 1) verify the basic nature of the thiolate-ligated ferryl in CPO-II, using croygenic reduction techniques, 2) determine if thiolate-ligated ferryls are basic in general, by examining the ferryl forms of P450BM-3 and P450nor, 3) determine if basic ferryls are a unique feature of thiolate-ligated hemes, by examining the protonation state of several histidine-ligated ferryl species as a function of pH, and 4) provide for the first time a detailed geometrical description of a thiolate-ligated compound I (the high-valent intermediate responsible for hydrogen abstraction in thiolate-ligated heme-enzymes).

National Institute of Health (NIH)
National Center for Research Resources (NCRR)
Biotechnology Resource Grants (P41)
Project #
Application #
Study Section
Special Emphasis Panel (ZRG1-BPC-E (40))
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Stanford University
Schools of Arts and Sciences
United States
Zip Code
Vickers, Chelsea; Liu, Feng; Abe, Kento et al. (2018) Endo-fucoidan hydrolases from glycoside hydrolase family 107 (GH107) display structural and mechanistic similarities to ?-l-fucosidases from GH29. J Biol Chem 293:18296-18308
Nguyen, Phong T; Lai, Jeffrey Y; Lee, Allen T et al. (2018) Noncanonical role for the binding protein in substrate uptake by the MetNI methionine ATP Binding Cassette (ABC) transporter. Proc Natl Acad Sci U S A 115:E10596-E10604
Aleman, Fernando; Tzarum, Netanel; Kong, Leopold et al. (2018) Immunogenetic and structural analysis of a class of HCV broadly neutralizing antibodies and their precursors. Proc Natl Acad Sci U S A 115:7569-7574
Herrera, Nadia; Maksaev, Grigory; Haswell, Elizabeth S et al. (2018) Elucidating a role for the cytoplasmic domain in the Mycobacterium tuberculosis mechanosensitive channel of large conductance. Sci Rep 8:14566
Lal, Neeraj K; Nagalakshmi, Ugrappa; Hurlburt, Nicholas K et al. (2018) The Receptor-like Cytoplasmic Kinase BIK1 Localizes to the Nucleus and Regulates Defense Hormone Expression during Plant Innate Immunity. Cell Host Microbe 23:485-497.e5
Pluvinage, Benjamin; Grondin, Julie M; Amundsen, Carolyn et al. (2018) Molecular basis of an agarose metabolic pathway acquired by a human intestinal symbiont. Nat Commun 9:1043
Beyerlein, Kenneth R; Jönsson, H Olof; Alonso-Mori, Roberto et al. (2018) Ultrafast nonthermal heating of water initiated by an X-ray Free-Electron Laser. Proc Natl Acad Sci U S A 115:5652-5657
Yoshizawa, Takuya; Ali, Rustam; Jiou, Jenny et al. (2018) Nuclear Import Receptor Inhibits Phase Separation of FUS through Binding to Multiple Sites. Cell 173:693-705.e22
Dods, Robert; Båth, Petra; Arnlund, David et al. (2017) From Macrocrystals to Microcrystals: A Strategy for Membrane Protein Serial Crystallography. Structure 25:1461-1468.e2
de Vries, Robert P; Tzarum, Netanel; Peng, Wenjie et al. (2017) A single mutation in Taiwanese H6N1 influenza hemagglutinin switches binding to human-type receptors. EMBO Mol Med 9:1314-1325

Showing the most recent 10 out of 604 publications