A biophysical characterization of the folded domains of KCTD12: insights into interaction with the GABAB2 receptor. Issue 10 (29th August 2013)

• Record Type: Journal Article
• Authors: Correale, Stefania; Esposito, Carla; Pirone, Luciano; Vitagliano, Luigi; Gaetano, Sonia Di; Pedone, Emilia
• Is Part Of: Journal of molecular recognition. Volume 26:Issue 10(2013:Oct.)
• Page Start: 488
• Page End: 495
• Publication Date: 2013-08-29
• Subjects: KCTD12 -- GABAB2 receptor -- oligomerization state -- interaction studies -- peptide design -- CD spectroscopy; Molecular recognition -- Periodicals; Models, Molecular -- Periodicals; Molecular Conformation -- Periodicals; Molecular Sequence Data -- Periodicals; Molecular Structure -- Periodicals; Carrier Proteins -- Periodicals; 572.8
• DOI: 10.1002/jmr.2291
• Languages: English
• ISSNs: 0952-3499

Abstract

Abstract : 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 GABAB2 receptor. Secondary prediction methods and CD spectroscopy have shown that the N‐terminal domain KCTD12BTB assumes an α/β structure, whereas the C‐terminal domain KCTD12H1 is predominantly characterized by a β‐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 KCTD12BTB and KCTD12H1 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 KCTD12POZ/BTB for the C‐terminal region of GABAB2 shows that it falls in the low micromolar range. Interestingly, we also demonstrate that a GABAB2 ‐related peptide is able to bind KCTD12BTB with a very high affinity. This peptide may represent a useful tool for modulating KCTD12/GABAB2 interaction in vitro and may also constitute the starting point for the development of peptidomimetic compounds with a potential for therapeutic applications. Copyright © 2013 John Wiley & Sons, Ltd. Abstract : Structural data on the two KCTD12‐folded domains were obtained by CD spectroscopy. Light‐scattering experiment shows that both domains are tetrameric. Binding assays indicate that the two domains show a good affinity for each other. The affinity between KCTD12BTB and GABAB2‐Cdomain is in the low micromolar range. A GABAB2 ‐derived peptide that binds KCTD12BTB with high affinity was discovered.