Wyatt has announced the conclusion of a study into the Calypso system at the ABRF 2013 meeting.
In the study conducted by the Molecular Interactions Research Group (MIRG) of the Association of Biomolecular Research Facilities (ABRF), a pair of unknown proteins, prepared and characterised by the ABRF, was sent out to multiple labs to determine affinity and stoichiometry of binding.
In a single afternoon consisting of 2 CG-MALS runs, the Wyatt Calypso system correctly determined that one molecule of Protein Y (26.3 kDa) binds 2 molecules of Protein X (11.9 kDa), one with KD of 10 nM and the other with 14 µM.
According to the company, this analysis agreed with the extensive AUC and ITC measurements performed by ABRF prior to distributing the samples.
The CG-MALS measurement was the only solution-based measurement among the participating labs.
The others used surface plasmon resonance (SPR) instruments which require immobilisation of one of the binding partners.
Wyatt Technology claims that only four of 13 SPR labs correctly measured and interpreted the data, typically taking 1-2 days even though the chip immobilisation recipe and regeneration were provided by the organisers.
The company also claims that the affinities determined by SPR were significantly weaker than those found by any of the solution-based measurements (AUC, ITC, CG-MALS), indicating that, in this instance, immobilisation modifies the interaction.