Protein Requirements for CMI Services
CMI guidelines for protein concentration and amount for different CMI services. We recommend that users provide a concentration higher than the minimum recommended.
| Method | Notes | Buffer Notes | minimum volume (μl) | recommended minimum concentration |
|---|---|---|---|---|
Mass Photometry | per sample, triplicate | in storage buffer | 50 | Protein: ~200 nM (diluted to 10-20 nM) AAV: >1012 capsid/ml |
SEC-MALS | per injection | in storage buffer | 150 | mg/ml > 10/mass(KDa)* mg/ml ~100/mass(KDa), preferred |
DLS | per sample, duplicates | in storage buffer | 150 | mg/ml > 10/mass(KDa)* |
CD | per sample | in final buffer | 300 | ~ 0.1 mg/ml |
NanoDSF | per sample, duplicates | in final buffer | 50 | ~ 0.2 mg/ml Standard Capillaries ~ 0.05 mg/ml High Sensitivity Capillaries |
NanoDSF | buffer screen, 96 conditions | in storage buffer | 200 | ~ 2 mg/ml |
DSF, sypro | per sample, triplicates | in storage buffer | 50 | ~ 0.5 mg/ml |
DSF, sypro | buffer screen, 96 conditions | in storage buffer | 200 | ~ 2 mg/ml |
Nanobody Selection | per protein antigen, standard selection (4 rounds) | antigen buffer needs to be free of primary amines for chemical biotinylation | 1 ml | ~ 15 μM |
* Light Scattering Intensity is proportional to mass. A higher concentration (in mg/ml) of protein is required for small proteins than for large proteins. BSA, which is 67 KDa, and typically very pure, will give an excellent signal in MALS and DSL experiments at 2 mg/ml, and an acceptable signal at 0.2 mg/ml. For a protein that is 1/2 the mass, plan use a concentration in the 0.4-4 mg/ml range.