Eukaryotic-type carbonic anhydrase; Carbonic anhydrases are zinc metalloenzymes which catalyse the reversible hydration of carbon dioxide to bicarbonate.. CAs have essential roles in facilitating the transport of carbon dioxide and protons in the intracellular space, across biological membranes and in the layers of the extracellular space; they are also involved in many other processes, from respiration and photosynthesis in eukaryotes to cyanate degradation in prokaryotes. There are five known evolutionarily distinct CA families (alpha, beta, gamma, delta and epsilon) that have no significant sequence identity and have structurally distinct overall folds. Some CAs are membrane-bound, while others act in the cytosol; there are several related proteins that lack enzymatic activity. The active site of alpha-CAs is well described, consisting of a zinc ion coordinated through 3 histidine residues and a water molecule/hydroxide ion that acts as a potent nucleophile. The enzyme employs a two-step mechanism: in the first step, there is a nucleophilic attack of a zinc-bound hydroxide ion on carbon dioxide; in the second step, the active site is regenerated by the ionisation of the zinc-bound water molecule and the removal of a proton from the active site. Beta- and gamma-CAs also employ a zinc hydroxide mechanism, although at least some beta-class enzymes do not have water directly coordinated to the metal ion.

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                   ....*....|....*....|....*....|....*....|....*....|.
gi 530424288    60 GGTRQSPINIQWRDSVYDPQLKPLRVSYEAASCLYIWNTGYLFQVEFDDAT 110
Cdd:smart01057  21 GGKRQSPIDIVTAEAQYDPSLKPLKLSYDQPTAKRILNNGHTVQVNFDDDG 71

Carbonic anhydrase [Inorganic ion transport and metabolism];

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gi 530424288  61 GTRQSPINIqwRDSVyDPQLKPLRVSYEAAScLYIWNTGYLFQVEFDDA 109
Cdd:COG3338   52 GKNQSPIDI--RTAI-KADLPPLKFDYKPTP-LEIVNNGHTIQVNVDPG 96

Eukaryotic-type carbonic anhydrase; Carbonic anhydrases are zinc metalloenzymes which catalyse the reversible hydration of carbon dioxide to bicarbonate.. CAs have essential roles in facilitating the transport of carbon dioxide and protons in the intracellular space, across biological membranes and in the layers of the extracellular space; they are also involved in many other processes, from respiration and photosynthesis in eukaryotes to cyanate degradation in prokaryotes. There are five known evolutionarily distinct CA families (alpha, beta, gamma, delta and epsilon) that have no significant sequence identity and have structurally distinct overall folds. Some CAs are membrane-bound, while others act in the cytosol; there are several related proteins that lack enzymatic activity. The active site of alpha-CAs is well described, consisting of a zinc ion coordinated through 3 histidine residues and a water molecule/hydroxide ion that acts as a potent nucleophile. The enzyme employs a two-step mechanism: in the first step, there is a nucleophilic attack of a zinc-bound hydroxide ion on carbon dioxide; in the second step, the active site is regenerated by the ionisation of the zinc-bound water molecule and the removal of a proton from the active site. Beta- and gamma-CAs also employ a zinc hydroxide mechanism, although at least some beta-class enzymes do not have water directly coordinated to the metal ion.

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                   ....*....|....*....|....*....|....*....|....*....|.
gi 530424288    60 GGTRQSPINIQWRDSVYDPQLKPLRVSYEAASCLYIWNTGYLFQVEFDDAT 110
Cdd:smart01057  21 GGKRQSPIDIVTAEAQYDPSLKPLKLSYDQPTAKRILNNGHTVQVNFDDDG 71

Carbonic anhydrase alpha, CA isozyme VII_like subgroup. Carbonic anhydrases (CAs) are zinc-containing enzymes that catalyze the reversible hydration of carbon dioxide in a two-step mechanism: a nucleophilic attack of a zinc-bound hydroxide ion on carbon dioxide, followed by the regeneration of the active site by ionization of the zinc-bound water molecule and removal of a proton from the active site. They are ubiquitous enzymes involved in fundamental processes like photosynthesis, respiration, pH homeostasis and ion transport. Most alpha CAs are monomeric enzymes. The zinc ion is complexed by three histidines. This vertebrate subgroup comprises isozyme VII. CA VII is the most active cytosolic enzyme after CA II, and may be highly expressed in the brain. Human CA VII may be a target of antiepileptic sulfonamides/sulfamates.

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                 ....*....|....*....|....*....|....*....|....*....|...
gi 530424288  61 GTRQSPINIQWRDSVYDPQLKPLRVSYEAASCLYIWNTGYLFQVEFDDATEAS 113
Cdd:cd03149    1 GNRQSPIDIVSSEAVYDPKLKPLSLSYDPCTSLSISNNGHSVMVEFDDSDDKT 53

Eukaryotic-type carbonic anhydrase;

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gi 530424288   52 WTVPVSVPGGTRQSPINIQWRDSVYDPQLKPLRVSY--EAASCLYIWNTGYLFQVEFDD 108
Cdd:pfam00194   6 WGKVYPSCGGKRQSPINIDTRKVRYDPSLPPLTFQGydVPPGKNTLTNNGHTVQVSLDD 64

Carbonic anhydrase alpha, prokaryotic-like subfamily. Carbonic anhydrases (CAs) are zinc-containing enzymes that catalyze the reversible hydration of carbon dioxide in a two-step mechanism: a nucleophilic attack of a zinc-bound hydroxide ion on carbon dioxide, followed by the regeneration of the active site by ionization of the zinc-bound water molecule and removal of a proton from the active site. They are ubiquitous enzymes involved in fundamental processes like photosynthesis, respiration, pH homeostasis and ion transport. Most alpha CAs are monomeric enzymes. The zinc ion is complexed by three histidines. This sub-family includes bacterial carbonic anhydrase alpha, as well as plant enzymes such as tobacco nectarin III and yam dioscorin and, carbonic anhydrases from molluscs, such as nacrein, which are part of the organic matrix layer in shells. Other members of this family may be involved in maintaining pH balance, in facilitating transport of carbon dioxide or carbonic acid, or in sensing carbon dioxide levels in the environment. Dioscorin is the major storage protein of yam tubers and may play a role as an antioxidant. Tobacco Nectarin may play a role in the maintenace of pH and oxidative balance in nectar. Mollusc nacrein may participate in calcium carbonate crystal formation of the nacreous layer. This subfamily also includes three alpha carbonic anhydrases from Chlamydomonas reinhardtii (CAH 1-3). CAHs1-2 are localized in the periplasmic space. CAH1 faciliates the movement of carbon dioxide across the plasma membrane when the medium is alkaline. CAH3 is localized to the thylakoid lumen and provides CO2 to Rubisco.

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gi 530424288  61 GTRQSPINIQWRDSVYDpQLKPLRVSYEAAScLYIWNTGYLFQVEFDDA 109
Cdd:cd03124   18 GKNQSPIDITTKAVVSD-KLPPLNYNYKPTS-ATLVNNGHTIQVNFEGN 64

Carbonic anhydrase alpha related protein: groups X, XI and related proteins. This subgroup contains carbonic anhydrase related proteins (CARPs) X and XI, which have been implicated in various biological processes of the central nervous system. CARPs are sequence similar to carbonic anhydrases. Carbonic anhydrases are zinc-containing enzymes that catalyze the reversible hydration of carbon dioxide in a two-step mechanism. CARPs have lost conserved histidines involved in zinc binding and consequently their catalytic activity. CARP XI plays a role in the development of gastrointestinal stromal tumors.

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gi 530424288  61 GTRQSPINIQWRDSVYDPQLKPLRVSYEAASCLYIWNTGYLFQVEFDDAT 110
Cdd:cd03121   18 GRRQSPVDIEPSRLLFDPFLTPLRIDTGRKVSGTFYNTGRHVSFRPDKDP 67

Carbonic anhydrase alpha, CA_IV, CA_XV, like isozymes. Carbonic anhydrases (CAs) are zinc-containing enzymes that catalyze the reversible hydration of carbon dioxide in a two-step mechanism: a nucleophilic attack of a zinc-bound hydroxide ion on carbon dioxide, followed by the regeneration of the active site by ionization of the zinc-bound water molecule and removal of a proton from the active site. They are ubiquitous enzymes involved in fundamental processes like photosynthesis, respiration, pH homeostasis and ion transport. There are three evolutionary distinct groups - alpha, beta and gamma carbonic anhydrases - which show no significant sequence identity or structural similarity. Most alpha CAs are monomeric enzymes. The zinc ion is complexed by three histidine residues. This subgroup, restricted to animals, contains isozyme IV and similar proteins such as mouse CA XV. Isozymes IV is attached to membranes via a glycosylphosphatidylinositol (GPI) tail. In mammals, Isozyme IV plays crucial roles in kidney and lung function, amongst others. This subgroup also contains the dual domain CA from the giant clam, Tridacna gigas. T. gigas CA plays a role in the movement of inorganic carbon from the surrounding seawater to the symbiotic algae found in the clam's tissues. CA XV is expressed in several species but not in humans or chimps. Similar to isozyme CA IV, CA XV attaches to membranes via a GPI tail.

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gi 530424288  61 GTRQSPINIQWRDSVYDPQLKPLR-VSY-EAASCLYIWNTGYLFQVEFDDATEASG 114
Cdd:cd03117    1 GKRQSPINIVTKKVQYDENLTPFTfTGYdDTTTNWTITNNGHTVQVTLPDGAKISG 56