Characterization of the Nicotinamide Adenine Dinucleotide Biosynthesis Pathway and Regulatory Mechanisms in Streptococcus mutans.

ABSTRACT: NAD⁺ and its derivatives, which act as redox coenzymes, are crucial for cellular metabolism and energy production. Nevertheless, the processes by which Streptococcus mutans, a bacterium known for causing dental caries, synthesizes NAD⁺ are not well elucidated. Through a genome-wide screen, we identified the nicotinic acid salvage pathway and the evolutionarily incomplete PnuC-NadR pathway involved in NAD⁺ biosynthesis in S. mutans UA159. The nicotinic acid pathway is regulated by SmNiaR, a nicotinic acid-responsive transcription regulator featuring an N-terminal DNA-binding winged helix-turn-helix-like domain and a C-terminal 3-histidine domain. Notably, a single-site amino acid substitution at site K97 in SmNiaR can reverse its DNA-binding ability, an effe

SUBMITTER: Yu H 

PROVIDER: S-EPMC12282500 | biostudies-literature | 2025 Jul

REPOSITORIES: biostudies-literature