Abstact

Biaryl motifs are fundamental structural elements in many pharmaceuticals, agrochemicals, and advanced materials. Traditional synthetic approaches for biaryl bond formation often require harsh conditions, costly catalysts, and pre-functionalized starting materials, which limit their efficiency, sustainability, and substrate scope. Enzymatic catalysis offers a greener alternative. However, biocatalysts capable of directly coupling halogenated biaryl compounds remain largely underexplored. Here, we report the functional characterization of the marine-derived cytochrome P450 enzyme Bmp7, which catalyzes the formation of halogenated biaryls. We first characterized the product profile of recombinant Bmp7 using its native substrate 2,4-dibromophenol (1) and confirmed the dominant ortho-ortho C-C homocoupled product as MC21-A. Screening a halogenated aromatic substrate library revealed that Bmp7 binds and catalyzes the coupling of 17 halogenated phenols, as evidenced by spectral shift assays, LC-HRMS, HRMS/MS and GC-MS analyses. Two homocoupled products were structurally confirmed by NMR analysis to possess ortho-ortho C-C linkages. In addition to efficient homocoupling, Bmp7 catalyzed heterocoupling reactions between substrate 1 and 16 other substrates, producing mixtures of homocoupled and heterocoupled halogenated biphenols. X-ray crystallography revealed the binding of two substrate 1 molecules within the active site, while DFT calculations supported a single-radical reaction mechanism, shedding light on the mechanistic basis of the coupling reaction. Together, these findings lay the groundwork for these findings establish a foundation for future efforts in enzyme engineering and the development of biocatalytic strategies for synthetic applications.