Circular dichroism and fluorescence of a tyrosine side-chain residue monitors the concentration-dependent equilibrium between U-shaped and coiled-coil conformations of a peptide derived from the catalytic core of HIV-1 integrase

Porumb, Horea; Zargarian, Loussiné; Merad, Hayate; Maroun, Richard G.; Mauffret, Olivier; Troalen, Frédéric; Fermandjian, Serge

doi:10.1016/j.bbapap.2004.01.005

Cited by 3 publications

(3 citation statements)

References 51 publications

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“…3b). Indeed, we had previously shown that peptide α 4 interacted with IN likely by forming a coiled-coil structure with its counterpart in the protein [50], [66].…”

Section: Resultsmentioning

confidence: 99%

An Unusual Helix Turn Helix Motif in the Catalytic Core of HIV-1 Integrase Binds Viral DNA and LEDGF

Merad

Porumb²,

Zargarian³

et al. 2009

PLoS ONE

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BackgroundIntegrase (IN) of the type 1 human immunodeficiency virus (HIV-1) catalyzes the integration of viral DNA into host cellular DNA. We identified a bi-helix motif (residues 149–186) in the crystal structure of the catalytic core (CC) of the IN-Phe185Lys variant that consists of the α4 and α5 helices connected by a 3 to 5-residue turn. The motif is embedded in a large array of interactions that stabilize the monomer and the dimer.Principal FindingsWe describe the conformational and binding properties of the corresponding synthetic peptide. This displays features of the protein motif structure thanks to the mutual intramolecular interactions of the α4 and α5 helices that maintain the fold. The main properties are the binding to: 1- the processing-attachment site at the LTR (long terminal repeat) ends of virus DNA with a Kd (dissociation constant) in the sub-micromolar range; 2- the whole IN enzyme; and 3- the IN binding domain (IBD) but not the IBD-Asp366Asn variant of LEDGF (lens epidermal derived growth factor) lacking the essential Asp366 residue. In our motif, in contrast to the conventional HTH (helix-turn-helix), it is the N terminal helix (α4) which has the role of DNA recognition helix, while the C terminal helix (α5) would rather contribute to the motif stabilization by interactions with the α4 helix.ConclusionThe motif, termed HTHi (i, for inverted) emerges as a central piece of the IN structure and function. It could therefore represent an attractive target in the search for inhibitors working at the DNA-IN, IN-IN and IN-LEDGF interfaces.

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“…3b). Indeed, we had previously shown that peptide α 4 interacted with IN likely by forming a coiled-coil structure with its counterpart in the protein [50], [66].…”

Section: Resultsmentioning

confidence: 99%

An Unusual Helix Turn Helix Motif in the Catalytic Core of HIV-1 Integrase Binds Viral DNA and LEDGF

Merad

Porumb²,

Zargarian³

et al. 2009

PLoS ONE

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“…In human cells, many cellular proteins, such as p53 (Lo et al , 2005) or viral proteins like the incoming retroviral HFV Gag protein, have been shown to interact with LC8 via a coiled‐coil domain (Petit et al , 2003). Full length HIV‐1 IN has been described as containing coiled‐coil‐forming domains (Porumb et al , 2004). For IN peptide fused to GFP, the coiled‐coil programme predicts such a structure only in the core domain (IN 150–180 ), but any coiled coil motif in the C‐terminal domain of IN is detected.…”

Section: Discussionmentioning

confidence: 99%

HIV‐1 integrase trafficking in S. cerevisiae: a useful model to dissect the microtubule network involvement of viral protein nuclear import

Desfarges

Salin

Calmels

et al. 2009

Yeast

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Intracellular transport of karyophilic cargos comprises translocation to the nuclear envelope and subsequent nuclear import. Small cargos such as isolated proteins can reach the nuclear envelope by diffusion but movement of larger structures depends on active translocation, typically using microtubules. Centripetal transport ends at the perinuclear microtubule organizing centre called the spindle pole body (SPB) in yeast.

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“…Our laboratory has been involved in developing spectroscopic tools for quantifying ligandmacromolecule interactions [16] and for fingerprinting (mostly) secondary structural features present in nucleic acids and proteins [7,8,[18][19][20].…”

Section: Discussionmentioning

confidence: 99%

Helical conformation of the AD1 peptide in the AML1-ETO–E-protein complex

Porumb

2009

Spectroscopy

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The AML1-ETO fusion protein is responsible for 15% of the acute myeloid leukaemias due to its interference with transcription activation by E-proteins. The eTAFH region of the AML1-ETO competes for the AD1 domain of E-protein, thereby preventing wild-type transcription activation. The structural details concerning the eTAFH–bound AD1 domain are not known. We have previously shown that the eTAFH–AD1 interaction is strong (Kd=28 nM, H. Porumb,Spectroscopy22 (2008), 251–260). The secondary structure prediction algorithms are undecided as to the conformation of bound AD1 peptide. Here we demonstrate by circular dichroism that the bound AD1 peptide is fully helical. This will facilitate modeling of the interaction and launches a challenge as to using synthetic peptides to out compete the eTAFH–E-protein interaction.

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Circular dichroism and fluorescence of a tyrosine side-chain residue monitors the concentration-dependent equilibrium between U-shaped and coiled-coil conformations of a peptide derived from the catalytic core of HIV-1 integrase

Cited by 3 publications

References 51 publications

An Unusual Helix Turn Helix Motif in the Catalytic Core of HIV-1 Integrase Binds Viral DNA and LEDGF

An Unusual Helix Turn Helix Motif in the Catalytic Core of HIV-1 Integrase Binds Viral DNA and LEDGF

HIV‐1 integrase trafficking in S. cerevisiae: a useful model to dissect the microtubule network involvement of viral protein nuclear import

Helical conformation of the AD1 peptide in the AML1-ETO–E-protein complex

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