TY - JOUR
T1 - Metalloproteins
T2 - Radical SAM catalysis via an organometallic intermediate with an Fe-[5′-C]-deoxyadenosyl bond
AU - Horitani, Masaki
AU - Shisler, Krista
AU - Broderick, William E.
AU - Hutcheson, Rachel U.
AU - Duschene, Kaitlin S.
AU - Marts, Amy R.
AU - Hoffman, Brian M.
AU - Broderick, Joan B.
N1 - Funding Information:
This work was funded by the NIH (grant GM 111097 to B.M.H. and grant GM 54608 to J.B.B.).
PY - 2016/5/13
Y1 - 2016/5/13
N2 - Radical S-adenosylmethionine (SAM) enzymes use a [4Fe-4S] cluster to cleave SAM to initiate diverse radical reactions. These reactions are thought to involve the 5′-deoxyadenosyl radical intermediate, which has not yet been detected. We used rapid freeze-quenching to trap a catalytically competent intermediate in the reaction catalyzed by the radical SAM enzyme pyruvate formate-lyase activating enzyme. Characterization of the intermediate by electron paramagnetic resonance and 13C, 57Fe electron nuclear double-resonance spectroscopies reveals that it contains an organometallic center in which the 5′ carbon of a SAM-derived deoxyadenosyl moiety forms a bond with the unique iron site of the [4Fe-4S] cluster. Discovery of this intermediate extends the list of enzymatic bioorganometallic centers to the radical SAM enzymes, the largest enzyme superfamily known, and reveals intriguing parallels to B12 radical enzymes.
AB - Radical S-adenosylmethionine (SAM) enzymes use a [4Fe-4S] cluster to cleave SAM to initiate diverse radical reactions. These reactions are thought to involve the 5′-deoxyadenosyl radical intermediate, which has not yet been detected. We used rapid freeze-quenching to trap a catalytically competent intermediate in the reaction catalyzed by the radical SAM enzyme pyruvate formate-lyase activating enzyme. Characterization of the intermediate by electron paramagnetic resonance and 13C, 57Fe electron nuclear double-resonance spectroscopies reveals that it contains an organometallic center in which the 5′ carbon of a SAM-derived deoxyadenosyl moiety forms a bond with the unique iron site of the [4Fe-4S] cluster. Discovery of this intermediate extends the list of enzymatic bioorganometallic centers to the radical SAM enzymes, the largest enzyme superfamily known, and reveals intriguing parallels to B12 radical enzymes.
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U2 - 10.1126/science.aaf5327
DO - 10.1126/science.aaf5327
M3 - Article
C2 - 27174986
AN - SCOPUS:84969203984
VL - 352
SP - 822
EP - 825
JO - Science
JF - Science
SN - 0036-8075
IS - 6287
ER -