Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 1990 Dec 15;265(35):21907-13.

The Zinc Fingers of Human poly(ADP-ribose) Polymerase Are Differentially Required for the Recognition of DNA Breaks and Nicks and the Consequent Enzyme Activation. Other Structures Recognize Intact DNA

Affiliations
  • PMID: 2123876
Free article

The Zinc Fingers of Human poly(ADP-ribose) Polymerase Are Differentially Required for the Recognition of DNA Breaks and Nicks and the Consequent Enzyme Activation. Other Structures Recognize Intact DNA

M Ikejima et al. J Biol Chem. .
Free article

Abstract

The recognition of double-stranded DNA breaks and single-stranded nicks by human poly(ADP-ribose) polymerase and the consequent enzymic activation were examined using derivatives of the enzyme expressed in Escherichia coli. The N-terminal 162 residues encompass two zinc fingers. Deletion or mutation of the first finger results in a loss of activation by DNA with either single-stranded or double-stranded damage. Destruction of the second finger reduces activation by double-stranded DNA breaks only slightly, but eliminates activation by single-stranded DNA nicks. These data suggest that activation by single-stranded DNA nicks requires two zinc fingers, but activation by double-stranded DNA breaks requires only the finger closer to the N terminus. Variant proteins that lack both zinc fingers are enzymically inactive but still exhibit weak DNA binding, which is independent of DNA damage. Thus, other regions are also capable of binding intact DNA, but the recognition of a strand nick or break which occasions the synthesis of poly(ADP-ribose) specifically requires the zinc fingers.

Similar articles

See all similar articles

Cited by 69 articles

See all "Cited by" articles

Publication types

LinkOut - more resources

Feedback