8U9J
The crystal structure of iron-bound human ADO C18S C239S variant at 2.02 Angstrom
Summary for 8U9J
| Entry DOI | 10.2210/pdb8u9j/pdb |
| Descriptor | 2-aminoethanethiol dioxygenase, FE (III) ION, GLYCEROL, ... (5 entities in total) |
| Functional Keywords | cysteamine dioxygenase (ec 1.13.11.19); iron-bound human ado, oxidoreductase |
| Biological source | Homo sapiens (human) |
| Total number of polymer chains | 2 |
| Total formula weight | 60888.35 |
| Authors | |
| Primary citation | Li, J.,Duan, R.,Liu, A. Cobalt(II)-Substituted Cysteamine Dioxygenase Oxygenation Proceeds through a Cobalt(III)-Superoxo Complex. J.Am.Chem.Soc., 146:18292-18297, 2024 Cited by PubMed Abstract: We investigated the metal-substituted catalytic activity of human cysteamine dioxygenase (ADO), an enzyme pivotal in regulating thiol metabolism and contributing to oxygen homeostasis. Our findings demonstrate the catalytic competence of cobalt(II)- and nickel(II)-substituted ADO in cysteamine oxygenation. Notably, Co(II)-ADO exhibited superiority over Ni(II)-ADO despite remaining significantly less active than the natural enzyme. Structural analyses through X-ray crystallography and cobalt K-edge excitation confirmed successful metal substitution with minimal structural perturbations. This provided a robust structural basis, supporting a conserved catalytic mechanism tailored to distinct metal centers. This finding challenges the proposed high-valent ferryl-based mechanism for thiol dioxygenases, suggesting a non-high-valent catalytic pathway in the native enzyme. Further investigation of the cysteamine-bound or a peptide mimic of -terminus RGS5 bound Co(II)-ADO binary complex revealed the metal center's high-spin ( = 3/2) state. Upon reaction with O, a kinetically and spectroscopically detectable intermediate emerged with a ground spin state of = 1/2. This intermediate exhibits a characteristic Co hyperfine splitting ( = 67 MHz) structure in the EPR spectrum alongside UV-vis features, consistent with known low-spin Co(III)-superoxo complexes. This observation, unique for protein-bound thiolate-ligated cobalt centers in a protein, unveils the capacities for O activation in such metal environments. These findings provide valuable insights into the non-heme iron-dependent thiol dioxygenase mechanistic landscape, furthering our understanding of thiol metabolism regulation. The exploration of metal-substituted ADO sheds light on the intricate interplay between metal and catalytic activity in this essential enzyme. PubMed: 38941563DOI: 10.1021/jacs.4c01871 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.02 Å) |
Structure validation
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