CBS domain-containing pyrophosphatase (CBS-PPase)

CBS domain-containing pyrophosphatases (CBS-PPases) are a specialized class of Family II inorganic pyrophosphatases found primarily in bacteria and archaea, including pathogens such as Clostridium perfringens and Eggerthella lenta (Jämsen et al., 2007; Anashkin et al., 2015). They are characterized by a regulatory insert containing a pair of cystathionine beta-synthase (CBS) domains, known as a Bateman module, which serves as an allosteric energy-sensing mechanism (Salminen et al., 2014). The enzyme's primary function is to catalyze the hydrolysis of inorganic pyrophosphate (PPi), a byproduct of numerous biosynthetic reactions; because high PPi levels can inhibit DNA, RNA, and protein synthesis, the activity of CBS-PPase is vital for maintaining metabolic flow. The enzyme is allosterically regulated by the cell's energy status, typically being inhibited by AMP or ADP and activated by ATP or diadenosine polyphosphate alarmones like Ap4A (Anashkin et al., 2015; Tuominen et al., 2010). Because human inorganic pyrophosphatases belong to a structurally distinct family (Family I) and lack these regulatory CBS domains, CBS-PPase is considered a highly selective and promising target for the development of novel antibacterial agents (Salminen et al., 2014; UniProt PPA1). Currently, research focuses on characterizing the cooperative ligand-binding network within the enzyme to identify synthetic modulators that can disrupt bacterial homeostasis.

Other names

CBS-PPaseFamily II inorganic pyrophosphataseNucleotide-regulated pyrophosphataseCBS domain-containing inorganic pyrophosphataseBateman module-containing pyrophosphatase

Modulation of intracellular inorganic pyrophosphate (PPi) levels; inhibition of the enzyme leads to the toxic accumulation of PPi, which prevents the forward progress of essential biosynthetic reactions—such as DNA, RNA, and protein synthesis—that rely on PPi hydrolysis for thermodynamic driving force.