Calypso

Composition-Gradient Multi-Angle Light Scattering (CG-MALS) employs a series of unfractionated samples of different composition or concentration in order to characterize macromolecular interactions such as reversible self- and hetero-association of proteins, reaction rates and affinities of irreversible aggregation, or virial coefficients. No special modifications - e.g. sample tagging or immobilization procedures - are necessary: samples are entirely in solution.

The Calypso system provides all that is necessary to simplify and automate CG-MALS measurements: the Calypso hardware - the SP3 triple-syringe pump accessory - for preparing and delivering Composition Gradient sequences to the detectors; and the Calypso software for controlling the SP3 while acquiring and analyzing data. Calypso interfaces with a Wyatt Technology light-scattering detector (DAWN-HELEOS, miniDAWN-TREOS), and a concentration detector such as Wyatt's Optilab rEX or a 3rd party on-line UV absorption detector. 

The primary analysis techniques supported by Calypso are:

  • Strong, specific reversible interactions: Kd (equilibrium dissociation constant) from picomolars to millimolars; stoichiometries of associating complexes; self and/or heteroassociations.
  • Weak, non-specific interactions: self- and cross-virial coefficients
  • Aggregation and other time-dependent reactions: stop-flow kinetics; t (equilibration or relaxation time) from seconds to hours.
  • Zimm plots: concentration gradients for determining MW (weight-averaged molar mass); A2, A3 (second and third virial coefficients); rg (root mean square radius, a.k.a. "radius of gyration")
  • Refractive increment: dn/dc
Calypso - Automated Batch Light Scattering System View enlarged version

 

Calypso's automation enhances productivity by improving repeatability and reliability, while minimizing time and effort. Relative to other techniques for characterizing protein interactions - as well as manual CG-MALS measurements - Calypso provides fast and accurate results.

  

Applications

  • Drug Discovery: Analyze impact of small molecules on protein-protein interactions; quantify enzyme/inhibitor or antibody/antigen interactions.
  • Process Improvement: Determine and adjust best A2 value for antibody purification and formulation or polymer production.
  • Protein Crystallation: Optimize buffer conditions through A2.
  • Self-assembly/Aggregation: Quantify impact of solvent ionic strength, pH, or excipients on polymerization or protein associations.
  • Biotech R&D: Characterize macromolecular binding strength and associated complex stoichiometry over a wide range of buffer compositions, time, and temperature scales.

Click here to read more about how Calypso quantifies reversible protein association.

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Wyatt Technology is the world leader in providing the most advanced macromolecular and nanoparticle characterization tools. These instruments and software may be used to determine the absolute molecular weight and or size of macromolecules and nanoparticles and include: multi-angle light scattering, dynamic light scattering, high through-put dynamic light scattering, field flow fractionation, refractive index and viscometry detection.