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2 State Reaction
- mtarca
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6 years 3 months ago #1
by mtarca
2 State Reaction was created by mtarca
Dear SPR Pages,
Can someone explain what a 2-state model is (in the Biacore software). I have not used this model before and when would it be applicable.
Thanks.
Can someone explain what a 2-state model is (in the Biacore software). I have not used this model before and when would it be applicable.
Thanks.
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- Arnoud
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6 years 3 months ago #2
by Arnoud
Replied by Arnoud on topic 2 State Reaction
Hi,
The conformational change or two state model assumes that after binding of the analyte to the ligand, the whole complex is rearranging itself following first order kinetics (1). The rate of change in conformation is assumed equal in both directions and before the analyte can dissociate, it must change to the first binding state.
It is not immediately apparent that a conformational change can have an effect on the response measured because it is mass-based and with a conformational change, no change in mass occurs. The effect is indirect because the second conformation alters the equilibrium between bound and free forms of the analyte. The second apparent rate constant increases with increasing analyte concentration (4). Post binding conformational changes are believed to be a feature of some receptor-hormone and antibody-antigen interaction (2, 3). All conformational change models should be confirmed with additional experiments such as ultracentrifugation, circular dichroisme or NMR.
There is much debate if you can measure conformational change with SPR (5).
Kind regards
Arnoud
1. De Crescenzo, G., Grothe, S., Lortie, R., et al.; Real-Time Kinetic Studies on the Interaction of Transforming Growth Factor alpha with the Epidermal Growth Factor Receptor Extracellular Domain Reveal a Conformational Change Model. Biochemistry (39) 31: 9466-9476; 2000.
2. Jonsson, U., Fagerstam, L., Ivarsson, B., et al.; Real-time biospecific interaction analysis using surface plasmon resonance and a sensor chip technology. Biotechniques (11) 5: 620-627; 1991.
3. Karlsson, R. and Falt, A.; Experimental design for kinetic analysis of protein-protein interactions with surface plasmon resonance biosensors. Journal of Immunological Methods (200) 1-2: 121-133; 1997.
4. Nahalkova, J., Svitel, J., Gemeiner, P., et al.; Affinity analysis of lectin interaction with immobilized C- and O- gylcosides studied by surface plasmon resonance assay. J.Biochem.Biophys.Methods (52) 1: 11-18; 2002.
5. Rich, R. L. and Myszka, D. G.; Survey of the year 2006 commercial optical biosensor literature. J.Mol.Recognit. (20) 5: 300-366; 2007.
The conformational change or two state model assumes that after binding of the analyte to the ligand, the whole complex is rearranging itself following first order kinetics (1). The rate of change in conformation is assumed equal in both directions and before the analyte can dissociate, it must change to the first binding state.
It is not immediately apparent that a conformational change can have an effect on the response measured because it is mass-based and with a conformational change, no change in mass occurs. The effect is indirect because the second conformation alters the equilibrium between bound and free forms of the analyte. The second apparent rate constant increases with increasing analyte concentration (4). Post binding conformational changes are believed to be a feature of some receptor-hormone and antibody-antigen interaction (2, 3). All conformational change models should be confirmed with additional experiments such as ultracentrifugation, circular dichroisme or NMR.
There is much debate if you can measure conformational change with SPR (5).
Kind regards
Arnoud
1. De Crescenzo, G., Grothe, S., Lortie, R., et al.; Real-Time Kinetic Studies on the Interaction of Transforming Growth Factor alpha with the Epidermal Growth Factor Receptor Extracellular Domain Reveal a Conformational Change Model. Biochemistry (39) 31: 9466-9476; 2000.
2. Jonsson, U., Fagerstam, L., Ivarsson, B., et al.; Real-time biospecific interaction analysis using surface plasmon resonance and a sensor chip technology. Biotechniques (11) 5: 620-627; 1991.
3. Karlsson, R. and Falt, A.; Experimental design for kinetic analysis of protein-protein interactions with surface plasmon resonance biosensors. Journal of Immunological Methods (200) 1-2: 121-133; 1997.
4. Nahalkova, J., Svitel, J., Gemeiner, P., et al.; Affinity analysis of lectin interaction with immobilized C- and O- gylcosides studied by surface plasmon resonance assay. J.Biochem.Biophys.Methods (52) 1: 11-18; 2002.
5. Rich, R. L. and Myszka, D. G.; Survey of the year 2006 commercial optical biosensor literature. J.Mol.Recognit. (20) 5: 300-366; 2007.
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