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Please use this identifier to cite or link to this item:
http://ir.nhri.org.tw/handle/3990099045/5492
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Title: | Binding of cGMP to the transducin-activated cGMP phosphodiesterase, PDE6, initiates a large conformational change involved in its deactivation |
Authors: | Yamazaki, A;Hayashi, F;Matsuura, I;Bondarenko, VA |
Contributors: | Division of Molecular and Genomic Medicine |
Abstract: | Retinal photoreceptor phosphodiesterase (PDE6), a key enzyme for phototransduction, consists of a catalytic subunit complex (Palphabeta) and two inhibitory subunits (Pgammas). Palphabeta has two non-catalytic cGMP-binding sites. Here, using bovine PDE preparations, we show the role of these cGMP-binding sites in PDE regulation. Palphabetagammagamma and its transducin-activated form, Palphabetagamma, contain two and one cGMP, respectively. Only Palphabetagamma shows [(3) H]cGMP binding with a K(d) approximately 50 nM and Pgamma inhibits the [(3) H]cGMP binding. Binding of cGMP to Palphabetagamma is suppressed during its formation, implying that cGMP binding is not involved in Palphabetagammagamma activation. Once bound to Palphabetagamma [(3) H]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 Palphabetagamma, and the amount of [(3) H]cGMP-bound Palphabetagamma trapped by a filter is spontaneously increased during its incubation. These results suggest that Palphabetagamma slowly changes its conformation after cGMP binding, i.e., after formation of Palphabetagamma containing two cGMPs. Binding of Pgamma greatly shortens the time to detect the increase in the filter-trapped level of [(3) H]cGMP-bound Palphabetagamma, but alters neither the level nor its Stokes radius. These results suggest that Pgamma accelerates the conformational change, but does not add another change. These observations are consistent with the view that Palphabetagamma changes its conformation during its deactivation and that the binding of cGMP and Pgamma is crucial for this change. These observations also imply that Palphabetagammagamma changes its conformation during its activation and that release of Pgamma and cGMP is essential for this change. |
Date: | 2011-06 |
Relation: | FEBS Journal. 2011 Jun;278(11):1854-1872. |
Link to: | http://dx.doi.org/10.1111/j.1742-4658.2011.08104.x |
JIF/Ranking 2023: | http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=NHRI&SrcApp=NHRI_IR&KeyISSN=1742-464X&DestApp=IC2JCR |
Cited Times(WOS): | https://www.webofscience.com/wos/woscc/full-record/WOS:000290687200007 |
Cited Times(Scopus): | http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=79956205703 |
Appears in Collections: | [松浦功] 期刊論文
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