کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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2021128 | 1069229 | 2009 | 7 صفحه PDF | دانلود رایگان |
The SH3-HOOK-GUK domains of the postsynaptic scaffolding proteins SAP90/PSD-95 and SAP97 are established targets of synaptic plasticity processes in the brain. A crucial molecular mechanism involved is the transition of this domain to different conformational states. We purified the SH3-HOOK-GUK domain of both proteins to examine variations in protein conformation and stability. As monitored by circular dichroism and differential scanning calorimetry, SAP97 (Tm = 64 °C) is significantly more thermal stable than SAP90/PSD-95 (Tm = 52 °C) and follows a bimodal phase transition. GdmCl-induced equilibrium unfolding of both proteins follows the two-state transitions and thus does not involve the accumulation of stable intermediate state(s). Equilibrium unfolding of SAP97 is highly cooperative from a native state to an unfolded state. In contrast, SAP90/PSD-95 follows a non-cooperative transition from native to unfolded states. A highly cooperative unfolding reaction in case of SAP97 indicates that the protein existed initially as a compact, well-folded structure, while the gradual, non-cooperative melting reaction in case of SAP90/PSD-95 indicates that the protein is in comparison more flexible.
Journal: Protein Expression and Purification - Volume 68, Issue 2, December 2009, Pages 201–207