Abstract
We have investigated by means of electron spin resonance (ESR) spectroscopy using two spin labels, Iodoacetamido-proxyl and 3-Maleimido-proxyl, the dynamics of two different regious around the active site of azurin, a copper containing blue protein. The ESR measurements of spin labeled azurin have been carried out in the 110–300 K temperature range on wet (H2O, D2O and ethanol/water mixtures) and lyophilized samples. The behaviours of the outer hyperfine splitting separation, 2A′ zz , of the ESR spectravs temperature of the lyophilized, and fully hydrated azurin in H2O and D2O suggest that the two spin labels are located in regions of the protein surface with different dynamics and polarity. Moreover, all differences in the 2A′ zz values shown by the spin labeled azurin in normal and heavy water as well as the temperature behaviour disappear when azurin is in ethanol/water mixtures. The results are discussed in terms of a close correlation between the molecular dynamics of the protein fragments to which the two spin labels are bound and the properties of the solvent used.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call