Streptavidin Homologues for Applications on Solid Surfaces at High Temperatures

The interaction between biotin and streptavidin is widely used in molecular biology due to its high affinity and stability. This bond is especially valuable in high-temperature environments such as PCR. While multiple streptavidin homologues exist, their performance on solid surfaces remains understudied. Prior research has shown that these proteins function well in solution, but no comprehensive comparison exists for solid-phase applications. This gap motivated the need for a systematic evaluation of how different streptavidin variants behave when immobilized on surfaces. The study aimed to address this by testing various streptavidin homologues in conditions that mimic real-world diagnostic assays. Understanding their behavior under such conditions is essential for optimizing assay design. The lack of comparative data on solid surfaces limits the ability to choose the most suitable variant for specific applications. This study aimed to provide a detailed analysis of streptavidin homologues under relevant experimental conditions.

The purpose of this study was to evaluate the performance of different streptavidin homologues on solid surfaces under conditions typical of nucleic acid detection and PCR. The researchers aimed to determine which variants are most suitable for hybridization, PCR, and melting point analysis. They focused on how these proteins interact with biotinylated oligonucleotides and DNA origamis on microbead surfaces. The study also aimed to assess the temperature stability of the SA/SAH-biotin bond. Understanding these interactions is important for developing reliable diagnostic assays. The researchers used a real-time fluorescence microscopy platform to monitor binding processes. This allowed them to apply precise temperature and time profiles during the experiments. The goal was to provide a systematic comparison that could guide future assay design.

The researchers immobilized various streptavidin homologues on microbeads and tested their ability to bind biotinylated oligonucleotides. They used a real-time fluorescence microscopy system to observe binding and hybridization processes. The platform enabled them to apply controlled temperature and time profiles during the experiments. They also tested the binding of DNA origamis to capture probes on the microbead surface. The study included streptavidin, core streptavidin, traptavidin, core traptavidin, neutravidin, and monomeric streptavidin. Hybridization efficiency was measured using fluorescence signals from complementary oligonucleotides. The researchers compared the temperature stability of the SA/SAH-biotin bond under different conditions. The data from these experiments helped identify the most suitable variants for high-temperature applications.

The study found that hybridization efficiencies were close to 100% for streptavidin, core streptavidin, traptavidin, and neutravidin. These variants performed similarly in hybridization, PCR, and melting point analysis. Core traptavidin and monomeric streptavidin were not suitable for the experiments. The SA/SAH-biotin bond showed temperature sensitivity when oligonucleotides were mono-biotinylated. Traptavidin exhibited the highest stability, followed by streptavidin and neutravidin. Mono-biotinylated oligonucleotides remained stable up to 70 °C. When oligonucleotides were bis-biotinylated, all SA/SAH-biotin bonds showed similar stability under PCR conditions. The study demonstrated that some streptavidin variants have slower biotin dissociation and increased mechanostability.

The authors concluded that streptavidin, core streptavidin, traptavidin, and neutravidin are equally suitable for hybridization, PCR, and melting point analysis. These variants performed well on solid surfaces under the tested conditions. Core traptavidin and monomeric streptavidin were not suitable for the experiments. The temperature stability of the SA/SAH-biotin bond depends on the biotinylation pattern of the oligonucleotides. Traptavidin showed the highest stability when oligonucleotides were mono-biotinylated. Bis-biotinylated oligonucleotides allowed for similar stability across all tested variants. The study supports the use of these streptavidin homologues in high-temperature applications. The findings provide a basis for selecting the most appropriate variant for specific assay designs.