2QEF

X-ray structure of 7-deaza-dG and Z3dU modified duplex CGCGAATXCZCG

Summary for 2QEF

• Entry DOI: 10.2210/pdb2qef/pdb
• Related: 2QEG
• Descriptor: DNA (5'-D(*DCP*DGP*DCP*DGP*DAP*DAP*DTP*(ZDU)P*DCP*(7GU)P*DCP*DG)-3') (2 entities in total)
• Functional Keywords: b-dna, z3du, 7-deaza-dg, dna
• Total number of polymer chains: 2
• Total formula weight: 7410.94

Authors

Wang, F.,Li, F.,Ganguly, M.,Marky, L.A.,Gold, B.,Egli, M.,Stone, M.P. (deposition date: 2007-06-25, release date: 2008-05-06, Last modification date: 2023-08-30)

Primary citation

Wang, F.,Li, F.,Ganguly, M.,Marky, L.A.,Gold, B.,Egli, M.,Stone, M.P.
A bridging water anchors the tethered 5-(3-aminopropyl)-2'-deoxyuridine amine in the DNA major groove proximate to the N+2 C.G base pair: implications for formation of interstrand 5'-GNC-3' cross-links by nitrogen mustards.
Biochemistry, 47:7147-7157, 2008

PubMed Abstract: Site-specific insertion of 5-(3-aminopropyl)-2'-deoxyuridine (Z3dU) and 7-deaza-dG into the Dickerson-Drew dodecamers 5'-d(C (1)G (2)C (3)G (4)A (5)A (6)T (7)T (8)C (9) Z (10)C (11)G (12))-3'.5'-d(C (13)G (14)C (15)G (16)A (17)A (18)T (19)T (20)C (21) Z (22)C (23)G (24))-3' (named DDD (Z10)) and 5'-d(C (1)G (2)C (3)G (4)A (5)A (6)T (7) X (8)C (9) Z (10)C (11)G (12))-3'.5'-d(C (13)G (14)C (15)G (16)A (17)A (18)T (19) X (20)C (21) Z (22)C (23)G (24))-3' (named DDD (2+Z10)) (X = Z3dU; Z = 7-deaza-dG) suggests a mechanism underlying the formation of interstrand N+2 DNA cross-links by nitrogen mustards, e.g., melphalan and mechlorethamine. Analysis of the DDD (2+Z10) duplex reveals that the tethered cations at base pairs A (5).X (20) and X (8).A (17) extend within the major groove in the 3'-direction, toward conserved Mg (2+) binding sites located adjacent to N+2 base pairs C (3).Z (22) and Z (10).C (15). Bridging waters located between the tethered amines and either Z (10) or Z (22) O (6) stabilize the tethered cations and allow interactions with the N + 2 base pairs without DNA bending. Incorporation of 7-deaza-dG into the DDD (2+Z10) duplex weakens but does not eliminate electrostatic interactions between tethered amines and Z (10) O (6) and Z (22) O (6). The results suggest a mechanism by which tethered N7-dG aziridinium ions, the active species involved in formation of interstrand 5'-GNC-3' cross-links by nitrogen mustards, modify the electrostatics of the major groove and position the aziridinium ions proximate to the major groove edge of the N+2 C.G base pair, facilitating interstrand cross-linking.

PubMed: 18549246
DOI: 10.1021/bi800375m

Experimental method

X-RAY DIFFRACTION (1.6 Å)