PDBsum entry 1p4z

DNA

PDB id: 1p4z

Contents

DNA/RNA

Metals

_NA ×3

Waters ×64

PDB id:

1p4z

Name:

DNA

Title:

Effect of sequence on the conformational geometry of DNA holliday junctions

Structure:

5'-d( Cp Cp Ap Gp Tp Ap Cp Tp Gp G)-3'. Chain: a. Engineered: yes

Source:

Synthetic: yes. Other_details: DNA was synthesized on an applied biosystems DNA synthesizer using phosphoramidite chemistry, with the trityl- protecting group left intact at the 5-terminal nucleotide, for subsequent hplc purification, then deprotected by treatment with 3% acetic acid for fifteen minutes, neutralized with ammonium hydroxide, and desalted on a sigma g-25 sephadex column.

Resolution:

2.00Å R-factor: 0.236 R-free: 0.268

Authors:

F.A.Hays,J.M.Vargason,P.S.Ho

Key ref:

F.A.Hays et al. (2003). Effect of sequence on the conformation of DNA holliday junctions. Biochemistry, 42, 9586-9597. PubMed id: 12911300 DOI: 10.1021/bi0346603

Date:

24-Apr-03 Release date: 02-Sep-03

DNA/RNA chain

C-C-A-G-T-A-C-T-G-G 10 bases

DOI no: 10.1021/bi0346603

Biochemistry 42:9586-9597 (2003)

PubMed id: 12911300

Effect of sequence on the conformation of DNA holliday junctions.

F.A.Hays, J.M.Vargason, P.S.Ho.

ABSTRACT

Structures of the DNA sequences d(CCGGCGCCGG) and d(CCAGTACbr(5)UGG) are presented here as four-way Holliday junctions in their compact stacked-X forms, with antiparallel alignment of the DNA strands. Thus, the ACC-trinucleotide motif, previously identified as important for stabilizing the junction, is now extended to PuCPy, where Pu is either an adenine or guanine, and Py is either a cytosine, 5-methylcytosine, or 5-bromouracil but not thymine nucleotide. We see that both sequence and base substituents affect the geometry of the junction in terms of the interduplex angle as well as the previously defined conformational variables, J(roll) (the rotation of the stacked duplexes about their respective helical axis) and J(slide) (the translational displacement of the stacked duplexes along their respective helical axis). The structures of the GCC and parent ACC containing junctions fall into a distinct conformational class that is relatively undistorted in terms of J(slide) and J(roll), with interduplex angles of 40-43 degrees. The substituted ACbr(5)U structure, however, is more akin to that of the distorted methylated ACm(5)C containing junction, with J(slide) (>or=2.3 A) and a similar J(roll) (164 degrees) opening the major groove-side of the junction, but shows a reduced interduplex angle. In contrast, the analogous d(CCAGTACTGG) sequence has to date been crystallized only as resolved B-DNA duplexes. This suggests that there is an electronic effect of substituents at the pyrimidine Py position on the stability of four-stranded junctions. The single-crystal structures presented here, therefore, show how sequence affects the detailed geometry, and subsequently, the associated stability and conformational dynamics of the Holliday junction.