Molecular characterization of the human carbonic anhydrase-related protein (HCA-RP VIII).
The very evolutionarily conserved human carbonic anhydrase-related polypeptide (CA-RP VIII) lacks the carbon-dioxide hydration-activity, characteristic of the enzymatically active carbonic anhydrases. We have expressed HCA-RP VIII as a glutathione-S-transferase fusion protein (GST-HCA-RP VIII). The purified HCA-RP VIII showed a substantially higher apparent molecular weight by gel-filtration compared to the molecular weight calculated from the amino acid sequence, indicating a larger than expected Stoke's radius. Like other studied CA's, the protein unfolds through two transitions at increasing concentrations of guanidine hydrochloride. The far-UV CD spectra of HCA-RP VIII indicates a secondary structure similar to that of the catalytically active HCA II. The very high sequence identity between human and mouse CA-RP VIII (98%), might indicate that the function of the protein involves binding of another protein. However, an attempt to use the GST-HCA-RP VIII fusion protein to affinity purify a ligand was unsuccessful.
Bergenhem
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Institute of Gerontology, University of Michigan, Ann Arbor 48109-0618, USA. nchb@novo.dk
Hallberg
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Wisén
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D014408:Biomarkers, Tumor; D002256:Carbonic Anhydrases / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D002942:Circular Dichroism; D004926:Escherichia coli / Q000235:genetics; D006801:Humans; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000302:isolation & purification*; D011489:Protein Denaturation; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D047908:Intracellular Signaling Peptides and Proteins
D014408:Biomarkers, Tumor; D002256:Carbonic Anhydrases; D009419:Nerve Tissue Proteins; D011994:Recombinant Proteins; C512821:Car8 protein, mouse; C512818:CA8 protein, human; D047908:Intracellular Signaling Peptides and Proteins