Molecular determinants of human dipeptidyl peptidase III sensitivity to thiol modifying reagents

Karačić, Zrinka; Špoljarić, Jasminka; Rožman, Marko; Abramić, Marija (2012) Molecular determinants of human dipeptidyl peptidase III sensitivity to thiol modifying reagents. Biological Chemistry, 393 (12). pp. 1523-1532. ISSN 1431-6730

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Official URL: https://www.degruyter.com/view/j/bchm.2012.393.iss...

Abstract

Human dipeptidyl peptidase III (DPP III) is a member of the metallopeptidase family M49, involved in protein metabolism and oxidative stress response. DPP III crystal structure shows the two lobe-like domains separated by a wide cleft. The human enzyme has a total of six cysteines, three in the lower (Cys19, Cys147, and Cys176) and three in the upper (Cys509, Cys519, and Cys654), catalytic, domain containing the active site zinc ion. To elucidate the molecular basis of this enzyme’s susceptibility to sulfhydryl reagents, biochemical analysis of a set of Cys to Ala mutants was used, supported by mass spectrometry. Cys176, a residue 44 Å apart from the catalytic center of the ligand-free enzyme, was found responsible for the inactivation with the submicromolar concentration of an organomercurial compound, and three additional cysteines contributed to sensitivity to aromatic disulfides. Upon treatment with oxidized glutathione [glutathione disulfide (GSSG)], cysteine residues at positions 147, 176, and 654 were found glutathionylated. The mutational analysis confirmed the involvement of Cys176 and Cys654 in human DPP III inactivation by GSSG. Observation that Cys176, a residue quite distant from the active center, contributes to enzyme inactivation, indicates that the substrate-binding site of human DPP III comprises both lower and upper protein domain.

Item Type:

Article

Uncontrolled Keywords:

glutathionylation ; mass spectrometry ; metallopeptidase M49 ; reactive cysteines ; sulfhydryl reagent

Subjects:

NATURAL SCIENCES > Chemistry

Divisions:

Division of Physical Chemistry

Projects:

Project title	Project leader	Project code	Project type
Spektroskopija, kemijska svojstva i reakcije biološki aktivnih molekula-	Branka Kovač	098-0982915-2945	MZOS
Molekularna enzimologija i proteinske interakcije hidrolaza-	Marija Abramić	098-1191344-2938	MZOS

Depositing User:

Kristina Ciglar

Date Deposited:

10 Jan 2017 10:08

URI:

http://fulir.irb.hr/id/eprint/3314

DOI:

10.1515/hsz-2012-0181