Carbonic anhydrases (CA) are zinc-containing enzymes that catalyze the reversible hydration of carbon dioxide in a two-step mechanism in which the nucleophilic attack of a zinc-bound hydroxide ion on carbon dioxide is followed by the regeneration of an active site by ionization of the zinc-bound water molecule and removal of a proton from the active site. CAs are ubiquitous enzymes involved in fundamental processes like photosynthesis, respiration, pH homeostasis and ion transport. There are three evolutionarily distinct families of CAs (the alpha-, beta-, and gamma-CAs) which show no significant sequence identity or structural similarity. Within the beta-CA family there are four evolutionarily distinct clades (A through D). The beta-CAs are multimeric enzymes (forming dimers,tetramers,hexamers and octamers) which are present in higher plants, algae, fungi, archaea and prokaryotes.

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                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 496363651   1 MRIIISCMDRRLN--RYLDQWNdGNTVFVRNAGSNVG-----SLRDTLKLLkGADEIVVLPHTDCGAMGV 63
Cdd:cd03379    4 KLAIVTCMDARLDpeKALGLKL-GDAKVIRNAGGRVTddairSLVVSVYLL-GTREIIVIHHTDCGMLTF 71

Carbonic anhydrases (CA) are zinc-containing enzymes that catalyze the reversible hydration of carbon dioxide in a two-step mechanism in which the nucleophilic attack of a zinc-bound hydroxide ion on carbon dioxide is followed by the regeneration of an active site by ionization of the zinc-bound water molecule and removal of a proton from the active site. CAs are ubiquitous enzymes involved in fundamental processes like photosynthesis, respiration, pH homeostasis and ion transport. There are three evolutionarily distinct families of CAs (the alpha-, beta-, and gamma-CAs) which show no significant sequence identity or structural similarity. Within the beta-CA family there are four evolutionarily distinct clades (A through D). The beta-CAs are multimeric enzymes (forming dimers,tetramers,hexamers and octamers) which are present in higher plants, algae, fungi, archaea and prokaryotes.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 496363651   1 MRIIISCMDRRLN--RYLDQWNdGNTVFVRNAGSNVG-----SLRDTLKLLkGADEIVVLPHTDCGAMGV 63
Cdd:cd03379    4 KLAIVTCMDARLDpeKALGLKL-GDAKVIRNAGGRVTddairSLVVSVYLL-GTREIIVIHHTDCGMLTF 71

Carbonic anhydrase; This family includes carbonic anhydrases as well as a family of non-functional homologs related to YbcF.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 496363651    3 IIISCMDRRL--NRYLDQwndGN-TVFV-RNAGsNV---------GSLRDTLKLLKgADEIVVLPHTDCGAMgvvhKALS 69
Cdd:pfam00484   2 LIIGCSDSRVppELIFDT---GPgDLFVvRNAG-NLvppydlnvlASIEYAVEVLK-VKHIVVCGHSGCGAV----KAAL 72

                          90
                  ....*....|....*..
gi 496363651   70 GEKMPDVLNPLITPFLN 86
Cdd:pfam00484  73 DAAGPAELPGFIDNWLR 89

Carbonic anhydrases (CA) are zinc-containing enzymes that catalyze the reversible hydration of carbon dioxide in a two-step mechanism in which the nucleophilic attack of a zinc-bound hydroxide ion on carbon dioxide is followed by the regeneration of an active site by ionization of the zinc-bound water molecule and removal of a proton from the active site. CAs are ubiquitous enzymes involved in fundamental processes like photosynthesis, respiration, pH homeostasis and ion transport. There are three evolutionarily distinct families of CAs (the alpha-, beta-, and gamma-CAs) which show no significant sequence identity or structural similarity. Within the beta-CA family there are four evolutionarily distinct clades (A through D). The beta-CAs are multimeric enzymes (forming dimers,tetramers,hexamers and octamers) which are present in higher plants, algae, fungi, archaea and prokaryotes.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 496363651   1 MRIIISCMDRRLN--RYLDQWNdGNTVFVRNAGSNVG-----SLRDTLKLLkGADEIVVLPHTDCGAMGV 63
Cdd:cd03379    4 KLAIVTCMDARLDpeKALGLKL-GDAKVIRNAGGRVTddairSLVVSVYLL-GTREIIVIHHTDCGMLTF 71

Carbonic anhydrase; Carbonic anhydrases (CA) are zinc metalloenzymes which catalyze the reversible hydration of carbon dioxide. In Escherichia coli, CA (gene cynT) is involved in recycling carbon dioxide formed in the bicarbonate-dependent decomposition of cyanate by cyanase (gene cynS). By this action, it prevents the depletion of cellular bicarbonate. In photosynthetic bacteria and plant chloroplast, CA is essential to inorganic carbon fixation. Prokaryotic and plant chloroplast CA are structurally and evolutionary related and form a family distinct from the one which groups the many different forms of eukaryotic CA's.

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                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 496363651     4 IISCMDRRL--NRYLDQwndGN-TVFV-RNAGSNVG-SLRDTL-------KLLkGADEIVVLPHTDCGAMgvvhKALSGE 71
Cdd:smart00947  10 IIGCSDSRVppELIFGL---GPgDLFViRNAGNIVPpYDDGVLasleyavEVL-GVKEIVVCGHTDCGAV----KAALDD 81

                   ....*
gi 496363651    72 KMPDV 76
Cdd:smart00947  82 EPGLI 86