Cloned (Comment) | Organism |
---|---|
DNA and amino acid sequence determination and analysis, sequence comparisons and phylogenetic tree | Tridacna squamosa |
Localization | Comment | Organism | GeneOntology No. | Textmining |
---|---|---|---|---|
membrane | membrane-bound, at apical membrane of some epithelial cells surrounding the tertiary water channels and to a lesser extent at the apical membrane of some epithelial apical immunofluorescence epithelial cells as compared with the control. Presence of two transmembrane regions in the DDCA | Tridacna squamosa | 16020 | - |
additional information | the signal peptide (residue 1-22) is predicted to be extracellular, and the GPI anchor is predicted to be Ala576 located near the 3' end of the second CA domain | Tridacna squamosa | - |
- |
Metals/Ions | Comment | Organism | Structure |
---|---|---|---|
Zn2+ | required, zinc enzyme, one of the Zn2+-containing active sites might be located externally and the other one inside the cell. Conserved histidine residues (His116, His118, His141) coordinate the Zn2+-containing catalytic site | Tridacna squamosa |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
H2CO3 | Tridacna squamosa | - |
CO2 + H2O | - |
r |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Tridacna squamosa | A0A2R2Y2Q1 | - |
- |
Source Tissue | Comment | Organism | Textmining |
---|---|---|---|
ctenidium | DDCA is expressed predominantly in the ctenidium | Tridacna squamosa | - |
epithelial cell | at apical membrane of some epithelial cells surrounding the tertiary water channels and to a lesser extent at the apical membrane of some epithelial apical immunofluorescence epithelial cells as compared with the control | Tridacna squamosa | - |
mantle | - |
Tridacna squamosa | - |
additional information | the DDCA is localized apically in certain epithelial cells near the base of the ctenidial filament and the epithelial cells surrounding the tertiary water channels. No or very poor expression in inner mantle, foot muscle, byssal muscle, heart, hepatopancreas, and kidney of Tridacna squamosa kept in darkness for 12 h, immunofluorescent tissue distribution analysis | Tridacna squamosa | - |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
H2CO3 | - |
Tridacna squamosa | CO2 + H2O | - |
r |
Subunits | Comment | Organism |
---|---|---|
? | x * 66700, about, sequence calculation | Tridacna squamosa |
Synonyms | Comment | Organism |
---|---|---|
DDCA | - |
Tridacna squamosa |
dual-domain carbonic anhydrase | - |
Tridacna squamosa |
Organism | Comment | Expression |
---|---|---|
Tridacna squamosa | the transcript and protein levels of DDCA/DDCA in the ctenidium of Tridacna squamosa increase significantly after 6 and 12 h of exposure to light, respectively | up |
General Information | Comment | Organism |
---|---|---|
additional information | the deduced enzyme DDCA sequence contains two distinct alpha-CA domains, each with a specific catalytic site. Each alpha-CA domain of the DDCA has its own set of catalytic and active sites. The first alpha-CA domain comprised the three histidine residues (His116, His118, His141) which coordinate the Zn2+-containing catalytic site, the hydrophobic residues (Val143, Val164, Leu224, Val233, Trp235) that form the CO2 binding pocket, and the gatekeeper residues (Glu128, Thr226). In the first alpha-CA domain, the active binding site for HCO3- and H+ constitutes five hydrophilic residues (Asn85, His87, Gln114, Thr225, and Thr226), of which His87 acts as a proton shuttle for CO2 hydration. Similarly, the Zn2+-containing catalytic site (His391, His393, His416), the hydrophobic residues that form the CO2 binding pocket (Val418, Val439, Leu504, Val513, Trp515), and the gatekeeper residues (Glu403, Thr506) are conserved in the second alpha-CA domain. Unlike the first alpha-CA domain, six hydrophilic residues (Asn361, His363, Gln366, Gln389, Thr505, and Thr506) are found in the second alpha-CA domain, and His363 serves as a proton shuttle for CO2 hydration | Tridacna squamosa |
physiological function | the ctenidial DDCA is positioned to dehydrate HCO3- to CO2 in seawater, and to hydrate the CO2 that has permeated the apical membrane back to HCO3- in the cytoplasm. During insolation, the host clam needs to increase the uptake of inorganic carbon from the ambient seawater to benefit the symbiotic zooxanthellae. Only then can the symbionts conduct photosynthesis and share the photosynthates with the host. Enzyme DDCA might participate in the light-enhanced uptake and assimilation of exogenous inorganic carbon | Tridacna squamosa |