Phosphine binding as a structural probe of the chloroperoxidase active site: spectroscopic evidence for endogenous thiolate ligation to the heme iron

1985 ◽  
Vol 24 (25) ◽  
pp. 4339-4343 ◽  
Author(s):  
Masanori Sono ◽  
John H. Dawson ◽  
Lowell P. Hager
Keyword(s):  
Active Site ◽  
Heme Iron ◽  
Spectroscopic Evidence ◽  
Structural Probe

Strongly Coupled Redox-Linked Conformational Switching at the Active Site of the Non-Heme Iron-Dependent Dioxygenase, TauD

2019 ◽  
Author(s):  
Christopher John ◽  
Greg M. Swain ◽  
Robert P. Hausinger ◽  
Denis A. Proshlyakov
Keyword(s):  
Active Site ◽  
Structural Model ◽  
Heme Iron ◽  
Chemical Transformations ◽  
Experimental Conditions ◽  
Strongly Coupled ◽  
Non Heme Iron ◽  
Reversible Redox ◽  
Wide Range ◽  
Complex Structural

2-Oxoglutarate (2OG)-dependent dioxygenases catalyze C-H activation while performing a wide range of chemical transformations. In contrast to their heme analogues, non-heme iron centers afford greater structural flexibility with important implications for their diverse catalytic mechanisms. We characterize an <i>in situ</i> structural model of the putative transient ferric intermediate of 2OG:taurine dioxygenase (TauD) by using a combination of spectroelectrochemical and semi-empirical computational methods, demonstrating that the Fe (III/II) transition involves a substantial, fully reversible, redox-linked conformational change at the active site. This rearrangement alters the apparent redox potential of the active site between -127 mV for reduction of the ferric state and 171 mV for oxidation of the ferrous state of the 2OG-Fe-TauD complex. Structural perturbations exhibit limited sensitivity to mediator concentrations and potential pulse duration. Similar changes were observed in the Fe-TauD and taurine-2OG-Fe-TauD complexes, thus attributing the reorganization to the protein moiety rather than the cosubstrates. Redox difference infrared spectra indicate a reorganization of the protein backbone in addition to the involvement of carboxylate and histidine ligands. Quantitative modeling of the transient redox response using two alternative reaction schemes across a variety of experimental conditions strongly supports the proposal for intrinsic protein reorganization as the origin of the experimental observations.

scholarly journals Structural evidence for a reaction intermediate mimic in the active site of a sulfite dehydrogenase

2020 ◽  
Vol 56 (68) ◽  
pp. 9850-9853
Author(s):  
Ahmed Djeghader ◽  
Melanie Rossotti ◽  
Saleh Abdulkarim ◽  
Frédéric Biaso ◽  
Guillaume Gerbaud ◽  
...  
Keyword(s):  
Active Site ◽  
Spectroscopic Evidence ◽  
Reaction Intermediate

We provide structural and spectroscopic evidence for a molybdenum–phosphate adduct mimicking a proposed reaction intermediate in the active site of a prokaryotic sulfite oxidizing enzyme.

Kinetic and Spectroscopic Evidence for Active Site Inhibition of Human Aldose Reductase†,‡

Biochemistry ◽  
1996 ◽  
Vol 35 (34) ◽  
pp. 11196-11202 ◽  
Author(s):  
Takayuki Nakano ◽  
J. Mark Petrash
Keyword(s):  
Aldose Reductase ◽  
Active Site ◽  
Spectroscopic Evidence

Spectroscopic Evidence of Reversible Disassembly of the [FeFe] Hydrogenase Active Site

2017 ◽  
Vol 8 (16) ◽  
pp. 3834-3839 ◽  
Author(s):  
Patricia Rodríguez-Maciá ◽  
Edward Reijerse ◽  
Wolfgang Lubitz ◽  
James A. Birrell ◽  
Olaf Rüdiger
Keyword(s):  
Active Site ◽  
Spectroscopic Evidence

scholarly journals Crystal structures of human 3-hydroxyanthranilate 3,4-dioxygenase with native and non-native metals bound in the active site

2017 ◽  
Vol 73 (4) ◽  
pp. 340-348 ◽  
Author(s):  
Lakshmi Swarna Mukhi Pidugu ◽  
Heather Neu ◽  
Tin Lok Wong ◽  
Edwin Pozharski ◽  
John L. Molloy ◽  
...  
Keyword(s):  
Active Site ◽  
Metal Binding ◽  
Inductively Coupled Plasma ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Kynurenine Pathway ◽  
Heme Iron ◽  
Resonance Spectroscopy ◽  
Extradiol Dioxygenase ◽  
Paramagnetic Resonance ◽  
Tryptophan Degradation

3-Hydroxyanthranilate 3,4-dioxygenase (3HAO) is an enzyme in the microglial branch of the kynurenine pathway of tryptophan degradation. 3HAO is a non-heme iron-containing, ring-cleaving extradiol dioxygenase that catalyzes the addition of both atoms of O2to the kynurenine pathway metabolite 3-hydroxyanthranilic acid (3-HANA) to form quinolinic acid (QUIN). QUIN is a highly potent excitotoxin that has been implicated in a number of neurodegenerative conditions, making 3HAO a target for pharmacological downregulation. Here, the first crystal structure of human 3HAO with the native iron bound in its active site is presented, together with an additional structure with zinc (a known inhibitor of human 3HAO) bound in the active site. The metal-binding environment is examined both structurally andviainductively coupled plasma mass spectrometry (ICP-MS), X-ray fluorescence spectroscopy (XRF) and electron paramagnetic resonance spectroscopy (EPR). The studies identified Met35 as the source of potential new interactions with substrates and inhibitors, which may prove useful in future therapeutic efforts.

Spectroscopic evidence supporting neutral thiol ligation to ferrous heme iron

2018 ◽  
Vol 23 (7) ◽  
pp. 1085-1092 ◽  
Author(s):  
Masanori Sono ◽  
Shengfang Sun ◽  
Anuja Modi ◽  
Mark S. Hargrove ◽  
Bastian Molitor ◽  
...  
Keyword(s):  
Heme Iron ◽  
Spectroscopic Evidence ◽  
Ferrous Heme
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