| Autor: |
Kuchenreuther JM; Department of Chemistry, University of California, Davis, Davis, CA 95616, USA., Myers WK, Stich TA, George SJ, Nejatyjahromy Y, Swartz JR, Britt RD |
| Jazyk: |
angličtina |
| Zdroj: |
Science (New York, N.Y.) [Science] 2013 Oct 25; Vol. 342 (6157), pp. 472-5. |
| DOI: |
10.1126/science.1241859 |
| Abstrakt: |
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. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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