Chakraborty, Subhra ; Chakraborty, Niranjan ; Jain, Deepti ; Salunke, Dinakar M. ; Datta, Asis (2002) Active site geometry of oxalate decarboxylase from Flammulina velutipes: role of histidine-coordinated manganese in substrate recognition Protein Science, 11 (9). pp. 2138-2147. ISSN 0961-8368
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Official URL: http://onlinelibrary.wiley.com/doi/10.1110/ps.0206...
Related URL: http://dx.doi.org/10.1110/ps.0206802
Abstract
Oxalate decarboxylase (OXDC) from the wood-rotting fungus Flammulina velutipes, which catalyzes the conversion of oxalate to formic acid and CO2 in a single-step reaction, is a duplicated double-domain germin family enzyme. It has agricultural as well as therapeutic importance. We reported earlier the purification and molecular cloning of OXDC. Knowledge-based modeling of the enzyme reveals a β-barrel core in each of the two domains organized in the hexameric state. A cluster of three histidines suitably juxtaposed to coordinate a divalent metal ion exists in both the domains. Involvement of the two histidine clusters in the catalytic mechanism of the enzyme, possibly through coordination of a metal cofactor, has been hypothesized because all histidine knockout mutants showed total loss of decarboxylase activity. The atomic absorption spectroscopy analysis showed that OXDC contains Mn2+ at up to 2.5 atoms per subunit. Docking of the oxalate in the active site indicates a similar electrostatic environment around the substrate-binding site in the two domains. We suggest that the histidine coordinated manganese is critical for substrate recognition and is directly involved in the catalysis of the enzyme.
Item Type: | Article |
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Source: | Copyright of this article belongs to Cold Spring Harbor Laboratory Press. |
Keywords: | Oxalate Decarboxylase; ECM Protein; Germin Motif; Knowledge-based Modeling; Knockout Mutants |
ID Code: | 9379 |
Deposited On: | 02 Nov 2010 12:19 |
Last Modified: | 16 May 2016 19:11 |
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