title: Characteristics of recombinant α-carbonic anhydrase of polyextremophilic bacterium Bacillus halodurans TSLV1.
abstract: Carbonic anhydrase (CA) is a biocatalyst that catalyzes the hydration of CO2 to bicarbonate and protons, thus useful in mitigating green house effect by sequestering CO2 from various point sources. An alkalistable and moderately thermostable α- carbonic anhydrase encoding gene (BhCA) from Bacillus halodurans TSLV1 has been cloned and expressed in Escherichia coli. A 31.4-fold enhancement in CA production was achieved due to cloning and expression in E. coli. About 50% of the CA produced was secreted when recombinant E. coli with BhCA-pET22b was cultivated in a medium with EDTA and lysozyme because of the efficient pelB leader sequence. rBhCA is a ∼75kDa homodimeric protein with a Tm of 72°C and T1/2 values of 66 and 24min at 50 and 60°C, respectively. SDM analysis revealed that H137, H139, H156 and H110 present in the active site play an important role in catalysis. Mineralization of CO2 using rBhCA led to the accelerated precipitation of CaCO3 in calcite form. rBhCA also functions as an efficient virtual peroxidase when Zn(2+) is substituted with Mn(2+).
authors.affiliation: Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi 110 021, India.
authors.forename: Shazia
authors.initials: S
authors.lastname: Faridi
authors.affiliation: Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi 110 021, India. Electronic address: tsnarayana@gmail.com.
authors.forename: T
authors.initials: T
authors.lastname: Satyanarayana
mesh_terms: D001407:Bacillus / Q000737:chemistry / Q000201:enzymology*; D002119:Calcium Carbonate / Q000737:chemistry; D002245:Carbon Dioxide / Q000737:chemistry; D002256:Carbonic Anhydrases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002384:Catalysis; D020134:Catalytic Domain; D004926:Escherichia coli / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic; D011994:Recombinant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D011994:Recombinant Proteins; D002245:Carbon Dioxide; D002256:Carbonic Anhydrases; D002119:Calcium Carbonate
keywords: Biomineralization; Recombinant α-carbonic anhydrase; Virtual peroxidase