The copper(II) binding centres of carbonic anhydrase are differently affected by reductants that ensure the redox intracellular environment.

The copper(II) binding centres of carbonic anhydrase are differently affected by reductants that ensure the redox intracellular environment. J Inorg Biochem. 2019 Jul 03;199:110759 Authors: Tabbì G, Magrì A, Rizzarelli E Abstract Copper is involved in several biological processes. The static and labile copper pools are controlled by means of a network of influx and efflux transporters, storage proteins, chaperones, transcription factors and small molecules as glutathione (GSH), which contributes to the cell reducing environment. To follow the fate of intracellular copper labile pool, a variant of human apocarbonic anhydrase has been proposed as fluorescent probe to monitor cytoplasmic Cu2+. Aware that in this cellular compartment copper ion is present as Cu+, electron spin resonance technique (ESR) was used to ascertain whether (bovine or human) carbonic anhydrase (CA) was able to accommodate Cu+ in the same sites occupied by Cu2+, in the presence of naturally occurring reducing agents such as ascorbate and GSH. Our ESR results on Cu2+ complexes with CA allow for a complete characterization of the two metal binding sites of the protein in solution. The use of the reported affinity constants of zinc in the catalytic site and of Cu2+ in the peripheral and catalytic site, allow us to obtain the speciation of copper species mimicking the spectroscopic study conditions. The different Cu2+ coordination features in the catalytic and the p...
Source: Journal of Inorganic Biochemistry - Category: Biochemistry Authors: Tags: J Inorg Biochem Source Type: research