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The corrinoid protein MtaC, which is natively involved in methyl transferase catalysis, catalyzes N -alkylation of aniline using ethyl diazoacetate. Our results show how the native preference of B 12 scaffolds for radical versus polar chemistry translates to non-native catalysis, which could guide selection of B 12 -dependent proteins for biocatalysis. MtaC also has high thermal stability and organic solvent tolerance, remaining folded even in pure methanol. 

Abstract Despite the unique reactivity of vitamin B₁₂and its derivatives, B₁₂‐dependent enzymes remain underutilized in biocatalysis. In this study, we repurposed the B₁₂‐dependent transcription factor CarH to enable non‐native radical cyclization reactions. An engineered variant of this enzyme, CarH*, catalyzes the formation γ‐ and δ‐lactams through either redox‐neutral or reductive ring closure with marked enhancement of reactivity and selectivity relative to the free B₁₂cofactor. CarH* also catalyzes an unusual spirocyclization by dearomatization of pendant arenes to produce bicyclic 1,3‐diene products instead of 1,4‐dienes provided by existing methods. These results and associated mechanistic studies highlight the importance of protein scaffolds for controlling the reactivity of B₁₂and expanding the synthetic utility of B₁₂‐dependent enzymes. 

Abstract Background Brassica oleracea includes several morphologically diverse, economically important vegetable crops, such as the cauliflower and cabbage. However, genetic variants, especially large structural variants (SVs), that underlie the extreme morphological diversity of B. oleracea remain largely unexplored. Results Here we present high-quality chromosome-scale genome assemblies for two B. oleracea morphotypes, cauliflower and cabbage. Direct comparison of these two assemblies identifies ~ 120 K high-confidence SVs. Population analysis of 271 B. oleracea accessions using these SVs clearly separates different morphotypes, suggesting the association of SVs with B. oleracea intraspecific divergence. Genes affected by SVs selected between cauliflower and cabbage are enriched with functions related to response to stress and stimulus and meristem and flower development. Furthermore, genes affected by selected SVs and involved in the switch from vegetative to generative growth that defines curd initiation, inflorescence meristem proliferation for curd formation, maintenance and enlargement, are identified, providing insights into the regulatory network of curd development. Conclusions This study reveals the important roles of SVs in diversification of different morphotypes of B. oleracea , and the newly assembled genomes and the SVs provide rich resources for future research and breeding.