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. Author manuscript; available in PMC: 2013 Jan 25.
Published in final edited form as: J Am Chem Soc. 2012 Dec 14;134(51):20858. doi: 10.1021/ja311284f

Correction to probing the reaction mechanism of spore photoproduct lyase (SPL) via diastereoselectively labeled dinucleotide SP TpT substrates

PMCID: PMC3553825  NIHMSID: NIHMS429809

Corrections to probing the reaction mechanism of spore photoproduct lyase (SPL) via diastereoselectively labeled dinucleotide SP TpT substrates

J. Am. Chem. Soc., 2011, 133 (27), pp 10434–10447 DOI: 10.1021/ja110196d

Linlin Yang,† § Gengjie Lin,† § Degang Liu,† Karl J. Dria, † Joshua Telser,|| and Lei Li †‡*

Page 10443: After carefully calibrating the 5′-dA and SP repair products generated from the wild-type spore photoproduct lyase (SPL) reaction, it was found that 3 equivalents of SAM support 5.4 turnovers upon a 3 hr enzyme reaction, not the 12 turnovers reported in Fig. 9A. The reported 5′-dA consumption in Fig. 9B was due to an unknown contaminant enzyme, but not the SPL activity to re-generate the S-adenosylmethionine. The corrected description of the reactivity of the wild-type SPL enzyme can be found in the following paper: Linlin Yang, Gengjie Lin, Renae S. Nelson, Yajun Jian, Joshua Telser, and Lei Li, Biochemistry, 2012, 51 (36), pp 7173–7188.

Page 10445: We are indebted to the cordial suggestion from Professor John-Stephen Taylor at the Washington University at St. Louis that the stereo-configuration of SP shown in Fig. 10 is not correct. The corrected Fig. 10 is shown below.

Figure 10.

Figure 10

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Newly proposed reaction mechanism for SPL catalyzed SP dimer repair. The 5′-dA radical generated from SAM reductive cleavage reaction takes the 6-HproR atom to yield a C6 radical on SP, the SP methylene bridge subsequently undergoes a homolytic cleavage to give a thymine methyl radical. (Note: This allyl radical is likely to delocalize to the thymine aromatic ring; the current drawing as a methyl radical is a simplified model to facilitate discussion) This radical abstracts an H atom back from an unknown protein residue, presumably C141, to generate a thiyl radical, releasing the repaired TpT. This thiyl radical either takes an H-atom back from the 5′-dA directly, or it reacts with other protein residues before the 5′-dA is re-oxidized to the radical form again. The resulting 5′-dA radical recombines with methionine to regenerate SAM and finish one catalytic cycle.

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