Screening of compounds interacting with HIV-1 proteinase using optical biosensor technology

Area of Science:

• Biochemistry
• Analytical Chemistry
• Drug Discovery

Background:

• Screening low-molecular-weight compounds against protein targets is crucial for drug discovery.
• Existing methods often require complex labeling or specific substrates.
• There is a need for a label-free, high-resolution biosensor assay for efficient compound screening.

Purpose of the Study:

• To develop and optimize a high-resolution optical biosensor assay for screening low-molecular-weight compounds.
• To demonstrate the assay's capability in identifying inhibitors of HIV-1 proteinase.
• To establish a generally applicable method for secondary screening of compound libraries.

Main Methods:

• Immobilization of HIV-1 proteinase on a sensor surface via direct amine coupling.
• Continuous flow of buffer with inhibitors and reference drugs.
• Label-free detection utilizing optical biosensing principles.
• Signal correction using a reference protein to account for buffer variations.
• Efficient sensor surface regeneration and system washing for reproducible results.

Main Results:

• The assay successfully distinguished HIV-1 inhibitors from non-inhibitors in a randomized compound series.
• Differences in interaction kinetics between compounds were accurately identified.
• The method revealed potential artifacts such as nonspecific binding and incomplete regeneration.
• High-affinity binders (nM range) required optimized regeneration protocols for consistent data.

Conclusions:

• The developed optical biosensor assay is a robust and sensitive tool for label-free screening of small molecules against protein targets.
• The assay simplifies analysis through graphical data display and report points.
• This method holds promise for general application in secondary screening of compound libraries for drug discovery.