Tyrosyl-DNA phosphodiesterase I catalytic mutants reveal an alternative nucleophile that can catalyze substrate cleavage

© 2015 by The American Society for Biochemistry and Molecular Biology, Inc..

Tyrosyl-DNA phosphodiesterase I (Tdp1) catalyzes the repair of 3'-DNA adducts, such as the 3'-phosphotyrosyl linkage of DNA topoisomerase I to DNA. Tdp1 contains two conserved catalytic histidines: a nucleophilic His (His(nuc)) that attacks DNA adducts to form a covalent 3'-phosphohistidyl intermediate and a general acid/base His (His(gab)), which resolves the Tdp1-DNA linkage. A His(nuc) to Ala mutant protein is reportedly inactive, whereas the autosomal recessive neurodegenerative disease SCAN1 has been attributed to the enhanced stability of the Tdp1-DNA intermediate induced by mutation of His(gab) to Arg. However, here we report that expression of the yeast His(nuc)Ala (H182A) mutant actually induced topoisomerase I-dependent cytotoxicity and further enhanced the cytotoxicity of Tdp1 His(gab) mutants, including H432N and the SCAN1-related H432R. Moreover, the His(nuc)Ala mutant was catalytically active in vitro, albeit at levels 85-fold less than that observed with wild type Tdp1. In contrast, the His(nuc)Phe mutant was catalytically inactive and suppressed His(gab) mutant-induced toxicity. These data suggest that the activity of another nucleophile when His(nuc) is replaced with residues containing a small side chain (Ala, Asn, and Gln), but not with a bulky side chain. Indeed, genetic, biochemical, and mass spectrometry analyses show that a highly conserved His, immediately N-terminal to His(nuc), can act as a nucleophile to catalyze the formation of a covalent Tdp1-DNA intermediate. These findings suggest that the flexibility of Tdp1 active site residues may impair the resolution of mutant Tdp1 covalent phosphohistidyl intermediates and provide the rationale for developing chemotherapeutics that stabilize the covalent Tdp1-DNA intermediate.

Medienart:

E-Artikel

Erscheinungsjahr:

2015

Erschienen:

2015

Enthalten in:

Zur Gesamtaufnahme - volume:290

Enthalten in:

The Journal of biological chemistry - 290(2015), 10 vom: 06. März, Seite 6203-14

Sprache:

Englisch

Beteiligte Personen:

Comeaux, Evan Q [VerfasserIn]
Cuya, Selma M [VerfasserIn]
Kojima, Kyoko [VerfasserIn]
Jafari, Nauzanene [VerfasserIn]
Wanzeck, Keith C [VerfasserIn]
Mobley, James A [VerfasserIn]
Bjornsti, Mary-Ann [VerfasserIn]
van Waardenburg, Robert C A M [VerfasserIn]

Links:

Volltext

Themen:

9007-49-2
DNA
DNA Adducts
DNA Damage
DNA Repair
DNA Topoisomerase
DNA Topoisomerases, Type I
EC 3.1.4.-
EC 5.99.1.2
Enzyme Mechanism
Enzyme Mutation
Journal Article
Multiprotein Complexes
Mutant Proteins
Phosphoric Diester Hydrolases
Protein-DNA Covalent Complexes
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Spinocerebellar Ataxia with Axonal Neuropathy 1
TDP1 protein, human
TOP1 protein, human
Tyrosyl-DNA Phosphodiesterase I

Anmerkungen:

Date Completed 18.05.2015

Date Revised 05.02.2021

published: Print-Electronic

PDB: 1NOP, 1Q32, 3SQ3

Citation Status MEDLINE

doi:

10.1074/jbc.M114.635284

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM245540245