| Autor: |
Manley OM; Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, United States., Tang H; Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States., Xue S; Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States., Guo Y; Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States., Chang WC; Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States., Makris TM; Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, United States.; Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States. |
| Abstrakt: |
BesC catalyzes the iron- and O 2 -dependent cleavage of 4-chloro-l-lysine to form 4-chloro-l-allylglycine, formaldehyde, and ammonia. This process is a critical step for a biosynthetic pathway that generates a terminal alkyne amino acid which can be leveraged as a useful bio-orthogonal handle for protein labeling. As a member of an emerging family of diiron enzymes that are typified by their heme oxygenase-like fold and a very similar set of coordinating ligands, recently termed HDOs, BesC performs an unusual type of carbon-carbon cleavage reaction that is a significant departure from reactions catalyzed by canonical dinuclear-iron enzymes. Here, we show that BesC activates O 2 in a substrate-gated manner to generate a diferric-peroxo intermediate. Examination of the reactivity of the peroxo intermediate with a series of lysine derivatives demonstrates that BesC initiates this unique reaction trajectory via cleavage of the C4-H bond; this process represents the rate-limiting step in a single turnover reaction. The observed reactivity of BesC represents the first example of a dinuclear-iron enzyme that utilizes a diferric-peroxo intermediate to capably cleave a C-H bond as part of its native function, thus circumventing the formation of a high-valent intermediate more commonly associated with substrate monooxygenations. |
