biostudies-literatureHirakawa YJapan Agency for Medical Research and DevelopmentJapan Society for the Promotion of Science105https://www.ebi.ac.uk/biostudies/studies/S-EPMC8132391biostudies-literatureUnknown19(1)<h4>Background</h4>Carbonic anhydrases (CAs) are universal metalloenzymes that catalyze the reversible conversion of carbon dioxide (CO₂) and bicarbonate (HCO₃^-). They are involved in various biological processes, including pH control, respiration, and photosynthesis. To date, eight evolutionarily unrelated classes of CA families (α, β, γ, δ, ζ, η, θ, and ι) have been identified. All are characterized by an active site accommodating the binding of a metal cofactor, which is assumed to play a central role in catalysis. This feature is thought to be the result of convergent evolution.<h4>Results</h4>Here, we report that a previously uncharacterized protein group, named "COG4337," constitutes metal-independent CAs from the newly discovered ι-class. Genes codinBMC biologyCharacterization of a novel type of carbonic anhydrase that acts without metal cofactors.PMC813239119H0328018K0635818H05419JP20am010107118K06358, 19H03280Fukuda KIshida MKinbara KTaira MSenda THirakawa YSenda MYu HYfalseCharacterization of a novel type of carbonic anhydrase that acts without metal cofactors.<h4>Background</h4>Carbonic anhydrases (CAs) are universal metalloenzymes that catalyze the reversible conversion of carbon dioxide (CO₂) and bicarbonate (HCO₃^-). They are involved in various biological processes, including pH control, respiration, and photosynthesis. To date, eight evolutionarily unrelated classes of CA families (α, β, γ, δ, ζ, η, θ, and ι) have been identified. All are characterized by an active site accommodating the binding of a metal cofactor, which is assumed to play a central role in catalysis. This feature is thought to be the result of convergent evolution.<h4>Results</h4>Here, we report that a previously uncharacterized protein group, named "COG4337," constitutes metal-independent CAs from the newly discovered ι-class. Genes codin2021-01-01T00:00:00Z2021 May2026-05-08T16:07:53.396Z2025-02-19T02:40:31.38ZS-EPMC81323913400627510.1186/s12915-021-01039-8