AI Article Synopsis
- The enzyme HydG uses S-adenosylmethionine (SAM) to break down l-tyrosine, producing carbon monoxide (CO) and cyanide (CN(-)), which are essential for building the H cluster of FeFe hydrogenase.
- Researchers utilized electron paramagnetic resonance (EPR) spectroscopy to study the reaction intermediates formed with specially labeled tyrosine substrates.
- The proposed reaction mechanism involves creating a tyrosine radical that ultimately leads to the formation of p-cresol and the conversion of dehydroglycine into CO and CN(-), critical components for the enzyme's assembly.*
Article Abstract
The radical S-adenosylmethionine (SAM) enzyme HydG lyses free l-tyrosine to produce CO and CN(-) for the assembly of the catalytic H cluster of FeFe hydrogenase. We used electron paramagnetic resonance spectroscopy to detect and characterize HydG reaction intermediates generated with a set of (2)H, (13)C, and (15)N nuclear spin-labeled tyrosine substrates. We propose a detailed reaction mechanism in which the radical SAM reaction, initiated at an N-terminal 4Fe-4S cluster, generates a tyrosine radical bound to a C-terminal 4Fe-4S cluster. Heterolytic cleavage of this tyrosine radical at the Cα-Cβ bond forms a transient 4-oxidobenzyl (4OB(•)) radical and a dehydroglycine bound to the C-terminal 4Fe-4S cluster. Electron and proton transfer to this 4OB(•) radical forms p-cresol, with the conversion of this dehydroglycine ligand to Fe-bound CO and CN(-), a key intermediate in the assembly of the 2Fe subunit of the H cluster.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1126/science.1241859 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!