8SV3

7-Deazapurines and 5-Halogenpyrimidine DNA duplex


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.51 Å
  • R-Value Free: 0.210 
  • R-Value Work: 0.177 
  • R-Value Observed: 0.179 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

Conformational Morphing by a DNA Analogue Featuring 7-Deazapurines and 5-Halogenpyrimidines and the Origins of Adenine-Tract Geometry.

Pallan, P.S.Lybrand, T.P.Rozners, E.Abramov, M.Schepers, G.Eremeeva, E.Herdewijn, P.Egli, M.

(2023) Biochemistry 62: 2854-2867

  • DOI: https://doi.org/10.1021/acs.biochem.3c00327
  • Primary Citation of Related Structures:  
    8SV3, 8SV4

  • PubMed Abstract: 

    Several efforts are currently directed at the creation and cellular implementation of alternative genetic systems composed of pairing components that are orthogonal to the natural dA/dT and dG/dC base pairs. In an alternative approach, Watson-Crick-type pairing is conserved, but one or all of the four letters of the A, C, G, and T alphabet are substituted by modified components. Thus, all four nucleobases were altered to create halogenated deazanucleic acid (DZA): dA was replaced by 7-deaza-2'-deoxyadenosine (dzA), dG by 7-deaza-2'-deoxyguanosine (dzG), dC by 5-fluoro-2'-deoxycytidine (FdC), and dT by 5-chloro-2'-deoxyuridine (CldU). This base-pairing system was previously shown to retain function in Escherichia coli . Here, we analyze the stability, hydration, structure, and dynamics of a DZA Dickerson-Drew Dodecamer (DDD) of sequence 5'-FdC-dzG-FdC-dzG-dzA-dzA-CldU-CldU-FdC-dzG-FdC-dzG-3'. Contrary to similar stabilities of DDD and DZA-DDD, osmotic stressing revealed a dramatic loss of hydration for the DZA-DDD relative to that for the DDD. The parent DDD 5'-d(CGCGAATTCGCG)-3' features an A-tract, a run of adenosines uninterrupted by a TpA step, and exhibits a hallmark narrow minor groove. Crystal structures─in the presence of RNase H─and MD simulations show increased conformational plasticity ("morphing") of DZA-DDD relative to that of the DDD. The narrow dzA-tract minor groove in one structure widens to resemble that in canonical B-DNA in a second structure. These changes reflect an indirect consequence of altered DZA major groove electrostatics (less negatively polarized compared to that in DNA) and hydration (reduced compared to that in DNA). Therefore, chemical modifications outside the minor groove that lead to collapse of major groove electrostatics and hydration can modulate A-tract geometry.


  • Organizational Affiliation

    School of Medicine, Department of Biochemistry, and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232, United States.


Macromolecules

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Ribonuclease H
A, B, C
142Halalkalibacterium haloduransMutation(s): 1 
Gene Names: rnhA
EC: 3.1.26.4
UniProt
Find proteins for Q9KEI9 (Halalkalibacterium halodurans (strain ATCC BAA-125 / DSM 18197 / FERM 7344 / JCM 9153 / C-125))
Explore Q9KEI9 
Go to UniProtKB:  Q9KEI9
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9KEI9
Sequence Annotations
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  • Reference Sequence

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Entity ID: 2
MoleculeChains LengthOrganismImage
Modified DNA
D, E
12synthetic construct
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.51 Å
  • R-Value Free: 0.210 
  • R-Value Work: 0.177 
  • R-Value Observed: 0.179 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 36.983α = 90
b = 89β = 100.44
c = 72.566γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
PDB_EXTRACTdata extraction
HKL-2000data reduction
HKL-2000data scaling
MOLREPphasing

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Volkswagen FoundationGermany92 851

Revision History  (Full details and data files)

  • Version 1.0: 2023-10-04
    Type: Initial release
  • Version 1.1: 2023-10-11
    Changes: Database references