Publication Date:
2013-10-26
Description:
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 Calpha-Cbeta 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.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kuchenreuther, Jon M -- Myers, William K -- Stich, Troy A -- George, Simon J -- Nejatyjahromy, Yaser -- Swartz, James R -- Britt, R David -- R01 GM104543/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 2013 Oct 25;342(6157):472-5. doi: 10.1126/science.1241859.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, University of California, Davis, Davis, CA 95616, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24159045" target="_blank"〉PubMed〈/a〉
Keywords:
Bacterial Proteins/*chemistry/genetics
;
Carbon Monoxide/chemistry
;
Catalysis
;
Catalytic Domain
;
Hydrogenase/*chemistry
;
Iron-Sulfur Proteins/*chemistry/genetics
;
Ligands
;
S-Adenosylmethionine/chemistry
;
Shewanella/*enzymology
;
Tyrosine/*chemistry
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
Permalink
