Presence of the propeptide on recombinant lysosomal dipeptidase controls both activation and dimerization.
Lysosomal dipeptidase catalyzes the hydrolysis of dipeptides with unsubstituted terminals. It is a homodimer and binds zinc. Dimerization is an important issue in understanding the enzyme's function. In this study, we investigated the influence of the propeptide on the folding and dimerization of recombinant lysosomal dipeptidase. For this purpose, we separately cloned and overexpressed the mature protein and the proenzyme. The overexpressed proteins were localized exclusively to insoluble inclusion bodies. Refolding of the urea-solubilized inclusion bodies showed that only dipeptidase lacking the propeptide was dimeric. The soluble renatured proenzyme was a monomer, although circular dichroism and fluorescence spectra of the proenzyme indicated the formation of secondary and tertiary structure. The propeptide thus controls dimerization, as well as activation, of lysosomal dipeptidase.
Dolenc
Iztok
I
Department of Biochemistry and Molecular Biology, Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia. iztok.dolenc@ijs.si
Pain
Roger
R
Turk
Vito
V
D002850:Chromatography, Gel; D002942:Circular Dichroism; D019281:Dimerization; D004150:Dipeptidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D008247:Lysosomes / Q000201:enzymology*; D017510:Protein Folding; D020673:Protein Renaturation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013050:Spectrometry, Fluorescence
D004792:Enzyme Precursors; D011994:Recombinant Proteins; D004150:Dipeptidases; C038937:dipeptidase