Conformation switch, proton-driven

Proton-Driven Conformation Switch in Asp-Oligopeptide and Model Compounds... 

Fig. 2. Simple two state allosteric model for qE in which the switch between quenched and unquenched conformation is driven by the effect of protonation and de-epoxidation. In this model LHCll can exist in two states, an unquenched conformation and a quenched conformation. Because the affinity of proton and zeaxanthin binding is greater in the quenched state, the ApH and de-epoxidation state will determine the equilibrium between these states. The existence of co-operativity indicates that these two states consist of a group of LHCll subunits which interact and change conformation in concert. The changed conformation, and intersubunit interaction, may give rise to quenching process itself In this model one or moreofthe different LHCll components may be involved.

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