Fluorescent CD4 probe for potential HIV-1 gp120 protein detection

Area of Science:

• Biochemistry
• Molecular Biology
• Biophysics

Background:

• The CD4 protein is a crucial receptor for HIV-1 entry.
• Developing sensitive detection methods for HIV-1 gp120 protein is vital for diagnostics and therapeutics.
• Fluorescent probes offer a sensitive approach for molecular interaction studies.

Purpose of the Study:

• To design and characterize a fluorescently modified CD4 domain 1 (mD1) protein probe.
• To utilize Förster resonance energy transfer (FRET) for detecting molecular interactions.
• To establish a tool for HIV-1 gp120 protein detection and inhibitor screening.

Main Methods:

• In vitro expression of a modified CD4 domain 1 (mD1) protein.
• Incorporation of a FRET pair: tryptophan (donor) and acridon-2-ylalanine (Acd, acceptor).
• Excitation at 260nm, monitoring emission at 420nm, and observing fluorescence quenching upon binding.

Main Results:

• The mD1 probe exhibited FRET, with energy transfer from tryptophan to Acd.
• Fluorescence at 420nm was quenched by Evans blue (EB) inhibitor and HIV-1 gp120 protein.
• Quenching demonstrated a concentration-dependent decrease in emission intensity, indicating binding.

Conclusions:

• The developed fluorescent CD4 probe is a sensitive tool for detecting HIV-1 gp120 protein.
• This probe can be used to screen for small molecules that inhibit the gp120-CD4 interaction.
• The mD1 probe represents a novel approach for HIV-1 research and drug discovery.