Part:BBa_K4665120
SazCA Carbonic Anhydrase
Biology and Usage
Biomineralisation is the process by which living organisms synthesise minerals (Dhami et al., 2013). One of the main metabolic pathways of microbial calcium carbonate production utilizes the zinc metallo-enzyme carbonic anhydrase as the catalyst of the reaction (Chaparro-Acuña et al., 2019). This pathway produces no pollutant byproduct, which is often the case with other biomineralisation pathways, and extracts CO2 from the atmosphere as a substrate for the reaction catalyzed by the carbonic anhydrase.
SazCA is a thermostable α-carbonic anhydrase derived from the thermophilic bacterium Sulfurihydrogenibium azorense and has been characterised as the fastest known carbonic anhydrase to date, possessing a kcat/KM value of approximately 3.5 × 108 M−1 s−1. SazCA facilitates the reversible hydration of carbon dioxide to bicarbonate and protons (see fig. 1) (De Simone et al., 2015; De Luca et al., 2013). This process creates alkaline conditions which increase the solubility of Ca2+ ions trapped on the extracellular matrix (EPS) of bacterial cells, which readily bond to HCO3-, facilitating the formation of calcium carbonate crystals (Anbu, et al. 2016).
Figure 1. The reversible hydration reaction of CO2 into HCO3-, followed by CaCO3 formation
The SazCA sequence was obtained from research by Zhu et al.(2022). This sequence has undergone codon optimization for E. coli and was employed in the BL21 DE3 chassis. A 6X-His tag is attached to SazCA, enabling detection using anti-His antibodies and purification through nickel immobilized metal affinity chromatography (IMAC).
Sequence and Features
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE WITH RFC[1000]
References
Anbu, P. et al. (March 1, 2016). Formations of calcium carbonate minerals by bacteria and its multiple applications. Springerplus 5(250). https://doi.org/10.1186/s40064-016-1869-2
Chaparro-Acuña, S.P., et al. (June, 2018). Soil bacteria that precipitate calcium carbonate: mechanism and applications of the process. Acta Agronómica 67(2). https://doi.org/10.15446/acag.v67n2.66109
De Luca, V. et al. (March 15, 2013). An α-carbonic anhydrase from the thermophilic bacterium Sulphurihydrogenibium azorense is the fastest enzyme known for the CO2 hydration reaction. Bioorganic & Medicinal Chemistry Letters, 21(6): 1465.1469. https://doi.org/10.1016/j.bmc.2012.09.047
De Simone, G., et al. (May 1, 2015). Crystal structure of the most catalytically effective carbonic anhydrase enzyme known, SazCA from the thermophilic bacterium Sulfurihydrogenibium azorense. Bioorganic & Medicinal Chemistry Letters, 1;25(9): 2002-2006. https://doi.org/10.1016/j.bmcl.2015.02.068
Zhu, Y., et al. (December 6, 2021). Surface display of carbonic anhydrase on Escherichia coli for CO2 capture and mineralisation. Synthetic and Systems biotechnology, 7(1): 460-473. https://doi.org/10.1016%2Fj.synbio.2021.11.008
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