Annealing of ssDNA and compaction of dsDNA by the HIV-1 nucleocapsid and Gag proteins visualized using nanofluidic channels
Journal article, 2019

The nucleocapsid protein NC is a crucial component in the human immunodeficiency virus type 1 life cycle. It functions both in its processed mature form and as part of the polyprotein Gag that plays a key role in the formation of new viruses. NC can protect nucleic acids (NAs) from degradation by compacting them to a dense coil. Moreover, through its NA chaperone activity, NC can also promote the most stable conformation of NAs. Here, we explore the balance between these activities for NC and Gag by confining DNA-protein complexes in nanochannels. The chaperone activity is visualized as concatemerization and circularization of long DNA via annealing of short single-stranded DNA overhangs. The first ten amino acids of NC are important for the chaperone activity that is almost completely absent for Gag. Gag condenses DNA more efficiently than mature NC, suggesting that additional residues of Gag are involved. Importantly, this is the first single DNA molecule study of full-length Gag and we reveal important differences to the truncated Δ-p6 Gag that has been used before. In addition, the study also highlights how nanochannels can be used to study reactions on ends of long single DNA molecules, which is not trivial with competing single DNA molecule techniques.


single DNA molecules





Kai Jiang

Chalmers, Biology and Biological Engineering, Food and Nutrition Science

Nicolas Humbert

University of Strasbourg

Sriram Kesarimangalam

Chalmers, Biology and Biological Engineering, Chemical Biology

Thiebault Lequeu

University of Strasbourg

Yii Lih Lin

Chalmers, Biology and Biological Engineering, Chemical Biology

Yves Mely

University of Strasbourg

Fredrik Westerlund

Chalmers, Biology and Biological Engineering, Chemical Biology

Quarterly Reviews of Biophysics

0033-5835 (ISSN) 1469-8994 (eISSN)

Vol. 52 e2-e2 e2

Areas of Advance

Nanoscience and Nanotechnology (SO 2010-2017, EI 2018-)

Subject Categories


Nano Technology





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4/6/2022 5