How HIV-1 Integrase Associates with Human Mitochondrial Lysyl-tRNA Synthetase

Area of Science:

• Virology
• Structural Biology
• Molecular Biology

Background:

• Human immunodeficiency virus type 1 (HIV-1) replication depends on incorporating host tRNA^Lys into viral particles.
• The GagPol polyprotein precursor interacts with mitochondrial lysyl-tRNA synthetase (mLysRS) and tRNA^Lys, crucial for initiating reverse transcription.

Purpose of the Study:

• To elucidate the three-dimensional (3D) architecture of the complex formed between HIV integrase and mLysRS.
• To understand the role of integrase in stabilizing the tRNA^Lys:mLysRS interaction.

Main Methods:

• Photo-crosslinking using pBpa to identify interacting residues between integrase and mLysRS.
• Molecular docking simulations to predict the 3D structure of the complex.
• Experimental validation using compensatory mutations to confirm the structural model.

Main Results:

• The C-terminal domain (CTD) of integrase is the primary binding site for mLysRS.
• Crosslinking identified specific residue interactions on the surfaces of mLysRS's catalytic domain and integrase's CTD.
• A validated structural model revealed that integrase binding stabilizes the tRNA^Lys:mLysRS interaction.

Conclusions:

• The C-terminal domain of HIV integrase plays a key role in binding mLysRS.
• The structural model provides insights into the molecular interactions critical for HIV replication.
• Integrase binding enhances the stability of the tRNA^Lys:mLysRS complex, essential for viral packaging.