Alves C, Cheng H, Tavanez JP, Casaca A, Gudima S, Roder H, Cunha C. Structural and nucleic acid binding properties of hepatitis delta virus small antigen. World J Virol 2017; 6(2): 26-35 [PMID: 28573087 DOI: 10.5501/wjv.v6.i2.26]
Corresponding Author of This Article
Celso Cunha, Associate Professor, Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, Rua da Junqueira 100, 1349-008 Lisboa, Portugal. ccunha@ihmt.unl.pt
Research Domain of This Article
Virology
Article-Type of This Article
Basic Study
Open-Access Policy of This Article
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World J Virol. May 12, 2017; 6(2): 26-35 Published online May 12, 2017. doi: 10.5501/wjv.v6.i2.26
Structural and nucleic acid binding properties of hepatitis delta virus small antigen
Carolina Alves, Hong Cheng, João Paulo Tavanez, Ana Casaca, Severin Gudima, Heinrich Roder, Celso Cunha
Carolina Alves, João Paulo Tavanez, Ana Casaca, Celso Cunha, Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, 1349-008 Lisboa, Portugal
Hong Cheng, Heinrich Roder, Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111, United States
Severin Gudima, Department of Microbiology, Molecular Genetics and Immunology, Kansas University Medical Center, Kansas City, KS 67874, United States
Author contributions: Alves C performed the majority of experiments; Cheng H performed the NMR and CD analysis; Casaca A performed production and purification of delta antigen; Tavanez JP, Gudima S and Roder H contributed to study design, provided critical discussions and wrote the manuscript; Cunha C designed and coordinated the research and wrote the manuscript.
Supported by Fundação para a Ciência e Tecnologia, FCT, to GHTM -UID/Multi/04413/2013; Carolina Alves and Ana Casaca were recipients of FCT PhD grants; João Paulo Tavanez is a recipient of a FCT post-doctoral fellowship SFRH/BPD/87494/2012.
Institutional review board statement: This study did not involve the use of any human and/or animal subjects.
Institutional animal care and use committee statement: This study did not involve the use of animal subjects.
Conflict-of-interest statement: The authors declare no conflicts of interest.
Data sharing statement: Technical appendix and dataset are available from the corresponding author at ccunha@ihmt.unl.pt.
Correspondence to: Celso Cunha, Associate Professor, Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, Rua da Junqueira 100, 1349-008 Lisboa, Portugal. ccunha@ihmt.unl.pt
Telephone: +351-21-3652620 Fax: +351-21-3632105
Received: December 20, 2016 Peer-review started: December 25, 2016 First decision: January 16, 2017 Revised: February 8, 2017 Accepted: February 28, 2017 Article in press: March 2, 2017 Published online: May 12, 2017 Processing time: 143 Days and 1.5 Hours
Abstract
AIM
To further characterize the structure and nucleic acid binding properties of the 195 amino acid small delta antigen, S-HDAg, a study was made of a truncated form of S-HDAg, comprising amino acids 61-195 (∆60HDAg), thus lacking the domain considered necessary for dimerization and higher order multimerization.
METHODS
Circular dichroism, and nuclear magnetic resonance experiments were used to assess the structure of ∆60HDAg. Nucleic acid binding properties were investigated by gel retardation assays.
RESULTS
Results showed that the truncated ∆60HDAg protein is intrinsically disordered but compact, whereas the RNA binding domain, comprising residues 94-146, adopts a dynamic helical conformation. We also found that ∆60HDAg fails to multimerize but still contains nucleic acid binding activity, indicating that multimerization is not essential for nucleic acid binding. Moreover, in agreement with what has been previously reported for full-length protein, no apparent specificity was found for the truncated protein regarding nucleic acid binding.
CONCLUSION
Taken together these results allowed concluding that ∆60HDAg is intrinsically disordered but compact; ∆60HDAg is not a multimer but is still capable of nucleic acid binding albeit without apparent specificity.
Core tip: The characterization of a truncated form of S-HDAg lacking amino acids 1-60, ∆60HDAg is reported. Structure of ∆60HDAg was assessed by circular dichroism and nuclear magnetic resonance and its nucleic acid binding properties were investigated using gel retardation assays. This study demonstrates for the first time that ∆60HDAg is intrinsically disordered and a monomer. Furthermore, ∆60HDAg can bind a wide variety of nucleic acids without apparent specificity.
