Structural basis for anaerobic alkane activation by a multisubunit glycyl radical enzyme.

ABSTRACT: X-succinate synthases (XSSs) are glycyl radical enzymes (GREs) that catalyze the addition of hydrocarbons to fumarate via radical chemistry, thereby activating them for microbial metabolism. To date, the only structurally characterized XSS is benzylsuccinate synthase (BSS), which functionalizes toluene. A distinct subclass of XSSs acts on saturated hydrocarbons, which possess much stronger C(sp³)-H bonds than toluene, suggesting mechanistic and structural differences from BSS. Here, we use cryogenic electron microscopy to determine the structure of one such enzyme, (1-methylalkyl)succinate synthase (MASS) from Azoarcus strain HxN1, which functionalizes n-alkanes (C6-C8). The structure reveals an asymmetric dimer in which both sides contain a catalytic α-subunit and

SUBMITTER: Andorfer MC 

PROVIDER: S-EPMC12358834 | biostudies-literature | 2025 Aug

REPOSITORIES: biostudies-literature