These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Structural distortions induced by integration host factor (IHF) at the H' site of phage lambda probed by (+)-CC-1065, pluramycin, and KMnO4 and by DNA cyclization studies.
    Author: Sun D, Hurley LH, Harshey RM.
    Journal: Biochemistry; 1996 Aug 20; 35(33):10815-27. PubMed ID: 8718873.
    Abstract:
    Integration Host Factor (IHF) is a sequence-specific DNA-bending protein that is proposed to interact with DNA primarily through the minor groove. We have used various chemical probes [(+)-CC-1065, a minor-groove-specific agent that alkylates N3 of adenine and traps bends into the minor groove; pluramycin, a minor-major-groove threading intercalator that alkylates N7 of guanine; KMnO4, which reacts more strongly with bases in denatured DNA] to gain more information on the interaction of IHF with the H' site of phage lambda. In addition to the 13-bp core consensus recognition element present at all IHF binding sites, the H' site also has an upstream AT-rich element that increases the affinity of IHF for this site. Our results reveal new details of IHF-DNA interaction at this site. Results with (+)-CC-1065 modification suggest that IHF interacts with the adenines on the 3'-side of the AT-rich element and likely induces a minor-groove bend in its vicinity, which in turn stabilizes the interaction. Pluramycin modification experiments suggest the presence of both short- and long-range structural perturbations (possible DNA unwinding events) on either side of the IHF contact region. Although IHF is known to induce a large bend in DNA at the H' site, no separation of base pairs was detected when the bent DNA was probed with KMnO4. DNA cyclization studies indicate a large magnitude (approximately 180 degrees) for the IHF-induced bend at the H' site, consistent with > 140 degrees bend estimated by gel electrophoresis methods. These studies suggest that IHF-induced DNA bending is accompanied by the introduction of a DNA node, DNA unwinding, and/or by some other DNA distortion. An enhanced binding and stability of IHF was observed on small circular DNA.
    [Abstract] [Full Text] [Related] [New Search]