Riboflavin synthase (RS)

Riboflavin synthase is an enzyme (EC 2.5.1.9) that catalyzes the final step in the biosynthesis of riboflavin (vitamin B2), transferring a four-carbon unit from one molecule of 6,7-dimethyl-8-ribityllumazine to another, producing riboflavin and 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione[1][5][2][7]. The enzyme forms homotrimers (in most bacteria, fungi, and plants) or homopentamers (in some Archaea) and functions by assembling the xylene ring of riboflavin via a highly specific and complex reaction[1][3]. The quaternary structure varies by organism, including unique multienzyme complexes with lumazine synthase in some bacteria[3][4]. Because animals do not have riboflavin synthase, it is an attractive target for the development of selective antimicrobial agents; inhibition of this enzyme can suppress the growth of pathogenic bacteria and fungi that require riboflavin biosynthesis[2][7]. Structural and mechanistic research supports its tractability as a target for new antibiotics.

Inhibitors block the catalytic activity of the enzyme, impeding riboflavin production and thereby hindering growth in pathogens that rely on de novo riboflavin synthesis[2][7]