TAILIEUCHUNG - Báo cáo khoa học: Binding of cGMP to the transducin-activated cGMP phosphodiesterase, PDE6, initiates a large conformational change involved in its deactivation

Retinal photoreceptor phosphodiesterase (PDE6), a key enzyme for photo-transduction, consists of a catalytic subunit complex (Pab) and two inhibi-tory subunits (Pcs). Pabhas two noncatalytic cGMP-binding sites. Here, using bovine PDE preparations, we show the role of these cGMP-binding sites in PDE regulation. | IFEBS Journal Binding of cGMP to the transducin-activated cGMP phosphodiesterase PDE6 initiates a large conformational change involved in its deactivation Akio Yamazaki1 2 3 Fumio Hayashi4 Isao Matsuura5 and Vladimir A. Bondarenko6 1 Kresge Eye Institute Wayne State University Detroit MI USA 2 Department of Ophthalmology Wayne State University Detroit MI USA 3 Department of Pharmacology Wayne State University Detroit MI USA 4 Department of Biology Kobe University Japan 5 Division of Molecular and Genomic Medicine NationalHealth Research Institutes Zhunan Town Taiwan 6 College of Osteopathic Medicine Touro University Henderson NV USA Keywords cGMP binding cGMP-binding-dependent protein conformationalchange GAF domains G-protein-mediated signal transduction PDE Correspondence V. A. Bondarenko College of Osteopathic Medicine Touro University Henderson NV 89014 USA Fax 1 702 777 1799 Tel 1 702 777 1806 E-mail Received 30 January 2011 revised 17 March 2011 accepted 22 March 2011 doi Retinal photoreceptor phosphodiesterase PDE6 a key enzyme for phototransduction consists of a catalytic subunit complex Pab and two inhibitory subunits Pys . Pap has two noncatalytic cGMP-binding sites. Here using bovine PDE preparations we show the role of these cGMP-binding sites in PDE regulation. Pabyy and its transducin-activated form Papc contain two and one cGMP respectively. Only Papc shows 3H cGMP binding with a Kd 50 nM and Py inhibits the 3H cGMP binding. Binding of cGMP to Papy is suppressed during its formation implying that cGMP binding is not involved in Pabyy activation. Once bound to Paby 3H cGMP is not dissociated even in the presence of a 1000-fold excess of unlabeled cGMP binding of cGMP changes the apparent Stokes radius of Paby and the amount of 3H cGMP-bound Paby trapped by a filter is spontaneously increased during its incubation. These results suggest that Paby slowly changes its conformation after .

TỪ KHÓA LIÊN QUAN
Đã phát hiện trình chặn quảng cáo AdBlock
Trang web này phụ thuộc vào doanh thu từ số lần hiển thị quảng cáo để tồn tại. Vui lòng tắt trình chặn quảng cáo của bạn hoặc tạm dừng tính năng chặn quảng cáo cho trang web này.