Characterization of the Streptococcus mutans SMU.1703c-SMU.1702c Operon Reveals Its Role in Riboflavin Import and Response to Acid Stress

Abstract

Dental caries form when acid produced by oral bacteria erodes tooth enamel. This process is driven by the fermentative metabolism of cariogenic bacteria, most notably Streptococcus mutans . Nutrient acquisition is key in the competitive oral cavity, and many organisms have evolved various strategies to procure carbon sources or necessary biomolecules. B vitamins, such as riboflavin, which many oral streptococci must scavenge from the oral environment, are necessary for survival within the competitive oral cavity. However, the primary mechanism and proteins involved in this process remain uncharacterized. This study is important because it identifies a key step in S. mutans riboflavin acquisition and cofactor generation, which may enable the development of novel anticaries treatment strategies via selective targeting of metabolite transporters.