科研之友
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摘要
Recent investigations have shown that members of the KCTD family play important roles in fundamental biological processes. Despite their roles, very limited information is available on their structures and molecular organization. By combining different experimental and theoretical techniques, we have here characterized the two folded domains of KCTD12, an integral component and modulator of the GABA(B2) receptor. Secondary prediction methods and CD spectroscopy have shown that the N-terminal domain KCTD12(BTB) assumes an / structure, whereas the C-terminal domain KCTD12(H1) is predominantly characterized by a -structure. Binding assays indicate that the two domains independently expressed show a good affinity for each other. This suggests that the overall protein is likely endowed with a rather compact structure with two interacting structured domains joint by a long disordered region. Notably, both KCTD12(BTB) and KCTD12(H1) are tetrameric when individually expressed. This finding could modify the traditional view that ascribes only to POZ/BTB domain a specific oligomerization role. The first quantification of the affinity of KCTD12(POZ/BTB) for the C-terminal region of GABA(B2) shows that it falls in the low micromolar range. Interestingly, we also demonstrate that a GABA(B2)-related peptide is able to bind KCTD12(BTB) with a very high affinity. This peptide may represent a useful tool for modulating KCTD12/GABA(B2) interaction in vitro and may also constitute the starting point for the development of peptidomimetic compounds with a potential for therapeutic applications.
- 出版日期2013-10
