3-Hexulose-6-phosphate synthase (HPS)

3-Hexulose-6-phosphate synthase (HPS) is a critical microbial enzyme that catalyzes the condensation of formaldehyde with D-ribulose-5-phosphate to form D-arabino-3-hexulose-6-phosphate [1, 2]. This reaction is the first step of the ribulose monophosphate (RuMP) cycle, which is essential for formaldehyde fixation and detoxification in methylotrophic bacteria and archaea [3, 5]. In addition to its role in C1-utilizing microorganisms, HPS is found in human pathogens such as Staphylococcus aureus, where it contributes to metabolic adaptation and resistance against oxidative and formaldehyde-induced stress [8, 14]. The enzyme belongs to the orotidine 5'-monophosphate decarboxylase (OMPDC) superfamily and typically requires divalent metal ions like Mg2+ or Mn2+ for maximal activity [5, 8]. From a therapeutic perspective, HPS is considered a promising target for novel antimicrobials because it is absent in the human genome, offering a high degree of selective toxicity [8, 14]. Experimental evidence indicates that halogenated hydroxynaphthalenecarboxanilides and colostrum hexasaccharide can modulate HPS levels or activity, leading to attenuated growth in methicillin-resistant S. aureus (MRSA) [1, 5]. By inhibiting the detoxification of formaldehyde, drugs targeting HPS can disrupt cellular homeostasis and biofilm integrity in infectious agents [2, 11]. Furthermore, HPS is a vital tool in synthetic biology for engineering formaldehyde detoxification systems and enabling synthetic methylotrophy in various industrial microorganisms [10, 16].

Other names

3-hexulosephosphate synthaseD-arabino-3-hexulose-6-phosphate formaldehyde-lyaseHexulose-6-phosphate synthase3-hexulose phosphate synthaseD-arabino-hex-3-ulose-6-phosphate formaldehyde-lyase (D-ribulose-5-phosphate-forming)HxlA

Inhibition of formaldehyde assimilation and detoxification leading to accumulation of toxic metabolic intermediates and disruption of C1 metabolism in pathogens.