Product News: Bio-Rad’s New ProteOn™ HTE Sensor Chip Suitable for Label-Free Analysis of Protein–Small Molecule Interactions

02 Mar 2012

Bio-Rad Laboratories, Inc.’s ProteOn™ HTE Sensor Chip provides a robust solution for pharmaceutical researchers studying the interaction of polyhistidine-tagged protein with small molecule drugs using surface plasmon resonance.

The chip’s innovative tris-NTA coated surface uses three NTA molecules instead of the traditional monomer version of the molecule. Tris-NTA yields a stronger binding interaction with the target, resulting in improved data quality compared to other biosensor solutions for capturing polyhistidine-tagged targets.

“In conversations with our customers and collaborators, we found that few satisfactory options exist today for scientists studying label-free histidine-tagged protein interactions,” said Jill Raymond, Bio-Rad Marketing Manager, Protein Interactions Technologies.

Other options that are available may result in the protein complex leaching off the surface, rendering the surface unsuitable for reuse. And data analysis may require intensive software corrections.

“The unfulfilled promises of other biosensor providers in this area were leaving our customers frustrated,” Raymond said. “This new chip, coupled with the previously launched HTG sensor chip for large molecule applications, means that Bio-Rad now provides a complete solution for customers wanting to work with polyhistidine-tag captured proteins in both small and large molecule applications.”

Better Performance

Used with Bio-Rad’s high-throughput ProteOn XPR36 system, the HTE sensor chip employs a tris-NTA complex on its surface to bind polyhistidine-tagged molecules. This allows researchers to improve binding stability, specificity, and data quality while reducing ligand decay. Bio-Rad has demonstrated that binding stability of polyhistidine-tagged proteins on the HTE sensor chip increased by up to 50% over mono-NTA chips and were approximately twice as selective.

“We’ve found that Bio-Rad’s new HTE sensor chips are capable of capturing high densities of many polyhistidine-tagged proteins, making it possible to characterize the binding of small molecules,” said Dr David Myszka, founder of Biosensor Tools, an SPR biosensor contract services and training provider.

Improved Reusability

Binding via polyhistidine tag is reversible. The HTE sensor chip performs better than anti-His capture surface solutions since it can be regenerated and does not require a change in the researcher's workflow.

This ability to reuse the HTE sensor chip multiple times eliminates chip-to-chip variability, enhances reproducibility, and decreases cost per data point by 90% compared to other commercially available chips, which have limited to no ability to be regenerated or reused.

“I love that the HTE sensor chips can be regenerated with a mixture of EDTA/SDS/NaOH and then still bind just about the same amount of target,” Myszka said.

The ProteOn HTE sensor chip also enables on-chip purification; i.e., capturing target proteins from crude media, thereby saving time, sample, and money required for purification. Earlier this year, Bio-Rad demonstrated a proof-of-concept SPR-MS workflow showing how the company’s SPR chips can be placed directly into a MALDI ionization chamber for mass spectrometry.