Genome-wide screening reveals a novel class of carbonic anhydrase-like inorganic carbon pumps in chemoautotrophic bacteria

Abstract

15 Many bacterial autotrophs rely on CO 2 concentrating mechanisms (CCMs) to assimilate carbon. Although 16 many CCM proteins have been identified, including a 200+ MDa protein organelle called the carboxysome, 17 a systematic screen of CCM components has not been carried out.

The MpsAB Bicarbonate Transporter Is Superior to Carbonic Anhydrase in Biofilm-Forming Bacteria with Limited CO 2 Diffusion

“…They were the first to describe that these transporters possess DIC uptake activity in Hydrogenovibrio crunogenus , a chemolithoautotroph from gammaproteobacteria and confirmed to transport DIC ( 11 ). Subsequently, these homologs which were named DABs, were also reported to accumulate HCO 3 − in a sulfur-oxidizing gammaproteobacterial chemolithoautotroph, Halothiobacillus neapolitanus ( 12 ). Surprisingly, DAB homologs were already described earlier in the nonautotrophic bacterium Staphylococcus aureus , where they were referred to as MpsAB (membrane-potential generating system) because they contribute to the membrane potential generation ( 13 ).…”

Isolation and Characterization of aHalomonasSpecies for Non-Axenic Growth-Associated Production of Bio-Polyesters from Sustainable Feedstocks

“…bluephagenesis TD01 [44] and H. boliviensis LC1 [45], as well as another isolate from the GSL north arm, H. utahensis DSM 3051 [46,47]. This particular gene, implicated in inorganic carbon transport, is common among autotrophs that also bear genes such as RuBisCO and/or carbonic anhydrase [29]. Given that CUBES01's genome does not appear to comprise a full Calvin-Benson-Bassham cycle, the presence of these genes in CUBES01 would suggest alternative roles in bicarbonate provision for essential metabolic pathways or in maintaining intracellular pH, which is connected to the metabolisms of alkaliphiles.…”

“…The genome of CUBES01 further contained genes associated with DABs [29] on contig 1 (MEC4768999.1 and MEC4768998.1) and contig 2 (MEC4769013.1). The DAB operon, consistent of dabA (PFAM: PF10070) and dabB (PFAM: PF00361), encodes an energy-coupled inorganic carbon (C i ) pump) [30], presumably encoding a hydrophilic protein that is thought to establish chemical equilibrium between CO 2 and HCO − 3 .…”