Send to

Choose Destination
J Struct Biol. 2004 Mar;145(3):263-71.

Conformational and enzymatic changes of 20S proteasome of rat natural killer cells induced by mono- and divalent cations.

Author information

Department of Molecular Biology and Immunology, Institute for Cancer Research, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, TX 76107, USA.


We have been investigated the relation between activation of "neutral" and "acidic" chymotrypsin-like (ChT-L) activity and conformational changes in the 20S proteasome complex from the rat natural killer (NK) cells induced by SDS, mono- and divalent cations. The conformational changes were monitored by tryptophan fluorescence and light scattering. It was revealed that the changes in the maximum position and contribution of the short-wavelength spectral component correlated with the alteration of ChT-L activity of the proteasome. Statistical analysis was applied to assign the fluorescence components with tryptophan residues based on the classification of calculated structural parameters of the environment of tryptophan fluorophores in protein. It was proposed that the emission of W13 from alpha6-subunit located near the cluster of highly conserved proteasome residues is mostly sensitive to the activation of the enzyme. We concluded that the expression of maximal ChT-L activity of 20S proteasome is associated with the conformational changes occurs in this cluster that lead to the proteasome open conformation, allowing substrate access into the proteolytic chamber.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center