Porcine circovirus 2 Rep domain complexed with a single-stranded DNA 10-mer comprising the cleavage site

Experimental Data Snapshot

  • Resolution: 2.03 Å
  • R-Value Free: 0.280 
  • R-Value Work: 0.229 
  • R-Value Observed: 0.232 

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Molecular underpinnings of ssDNA specificity by Rep HUH-endonucleases and implications for HUH-tag multiplexing and engineering.

Tompkins, K.J.Houtti, M.Litzau, L.A.Aird, E.J.Everett, B.A.Nelson, A.T.Pornschloegl, L.Limon-Swanson, L.K.Evans, R.L.Evans, K.Shi, K.Aihara, H.Gordon, W.R.

(2021) Nucleic Acids Res 49: 1046-1064

  • DOI: https://doi.org/10.1093/nar/gkaa1248
  • Primary Citation of Related Structures:  
    6WDZ, 6WE0, 6WE1

  • PubMed Abstract: 

    Replication initiator proteins (Reps) from the HUH-endonuclease superfamily process specific single-stranded DNA (ssDNA) sequences to initiate rolling circle/hairpin replication in viruses, such as crop ravaging geminiviruses and human disease causing parvoviruses. In biotechnology contexts, Reps are the basis for HUH-tag bioconjugation and a critical adeno-associated virus genome integration tool. We solved the first co-crystal structures of Reps complexed to ssDNA, revealing a key motif for conferring sequence specificity and for anchoring a bent DNA architecture. In combination, we developed a deep sequencing cleavage assay, termed HUH-seq, to interrogate subtleties in Rep specificity and demonstrate how differences can be exploited for multiplexed HUH-tagging. Together, our insights allowed engineering of only four amino acids in a Rep chimera to predictably alter sequence specificity. These results have important implications for modulating viral infections, developing Rep-based genomic integration tools, and enabling massively parallel HUH-tag barcoding and bioconjugation applications.

  • Organizational Affiliation

    Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Twin Cities, Minneapolis, MN 55455, USA.


Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
ATP-dependent helicase RepB [auth D],
D [auth G],
G [auth A]
115Porcine circovirus 2Mutation(s): 0 
Gene Names: Rep
Find proteins for Q8BB16 (Porcine circovirus 2)
Explore Q8BB16 
Go to UniProtKB:  Q8BB16
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ8BB16
Sequence Annotations
  • Reference Sequence

Find similar nucleic acids by:  Sequence   |   3D Structure  

Entity ID: 1
MoleculeChains LengthOrganismImage
DNA (5'-D(*TP*AP*GP*TP*AP*TP*TP*AP*CP*C)-3')A [auth C],
C [auth I],
E [auth F],
F [auth J]
10Porcine circovirus 2
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.03 Å
  • R-Value Free: 0.280 
  • R-Value Work: 0.229 
  • R-Value Observed: 0.232 
  • Space Group: P 64
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 99.527α = 90
b = 99.527β = 90
c = 73.695γ = 120
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
HKL-3000data reduction
HKL-3000data scaling
Cootmodel building

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United StatesGM119483
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United StatesGM118047

Revision History  (Full details and data files)

  • Version 1.0: 2020-12-16
    Type: Initial release
  • Version 1.1: 2021-03-17
    Changes: Database references
  • Version 1.2: 2023-10-18
    Changes: Advisory, Data collection, Database references, Refinement description