التفاصيل البيبلوغرافية
| العنوان: |
The solution structure of the transducin-α-uncoordinated 119 protein complex suggests occlusion of the Gβ1γ1-binding sites. |
| المؤلفون: |
Cheguru, Pallavi, Majumder, Anurima, Yadav, Ravi, Gopalakrishna, Kota N., Gakhar, Lokesh, Artemyev, Nikolai O. |
| المصدر: |
FEBS Journal; Feb2015, Vol. 282 Issue 3, p550-561, 12p |
| مصطلحات موضوعية: |
PHOTORECEPTORS, TRANSDUCIN, PROTEIN structure, BINDING sites, PROTEIN crosslinking, PHOSPHODIESTERASES |
| مستخلص: |
Uncoordinated 119 protein ( UNC119) is a partner of transducin-α subunit (Gαt) that is essential for transducin trafficking in rod photoreceptors. The interaction is known to involve binding of the acylated N terminus of Gαt to the hydrophobic pocket of UNC119. To gain insights into the mechanism of transducin trafficking, we isolated a highly pure protein complex between myristoylated chimeric Gαt (Gαt*) and UNC11950-240, and examined the solution structure by small angle X-ray scattering and chemical crosslinking. The solution structure of the Gαt- UNC11950-240 complex was derived with rigid body/ ab initio modeling against the small angle X-ray scattering data by use of known atomic structures of Gαt and UNC119, and a distance constraint based on the protein crosslinking with p-phenyldimaleimide. The model of the Gαt- UNC11950-240 complex indicates rotation and bending of the N-terminal α-helix of Gαt from its position in the structure of the heterotrimeric G-protein transducin (Gt). This allows a considerably more compact complex conformation, which also suggests a novel interface involving the switch II/α3-β5 surface of Gαt. Supporting a novel interface, UNC119 was found to bind full-length Gαt* more strongly than the Gαt N-terminal peptide. Furthermore, UNC119 competed with the effector molecule phosphodiesterase-6 γ-subunit, which is known to bind to the same surface of Gαt. The solution structure of the Gαt- UNC119 complex suggests that the ability of UNC119 to dissociate Gt subunits and release Gαt from the membrane is attributable to disruption and sterical occlusion of the Gβ1γ1-binding sites on Gαt. [ABSTRACT FROM AUTHOR] |
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| قاعدة البيانات: |
Complementary Index |
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