Three-dimensional structure of non-activated cGMP phosphodiesterase 6 and comparison of its image with those of activated forms

Naoko Kajimura, Matsuyo Yamazaki, Kosuke Morikawa, Akio Yamazaki, Kouta Mayanagi

研究成果: Contribution to journalArticle査読

38 被引用数 (Scopus)

抄録

Cyclic GMP phosphodiesterase (PDE6) in rod photoreceptors, a key enzyme in vertebrate phototransduction, consists of two homologous catalytic subunits (Pα and Pβ) and two identical regulatory subunits (Pγs). Pγ regulates the PDE activity through its direct interaction with transducin. Here, using electron microscopy and image analysis of single particles, we show the three-dimensional organization of the basic form of bovine PDE, Pαβγγ, and compare its average image with those of Pγ-released PDE. The structure of Pαβγγ appears to be a flattened bell-shape, with dimensions of 150 × 108 × 60 Å, and with a handle-like protrusion attached to the top of the structure. Except for the protrusion, the organization consists of two homologous structures arranged side by side, with each structure having three distinct regions, showing pseudo twofold symmetry. These characteristics are consistent with a model in which the overall structure of Pαβγγ is determined by hetero-dimerization of Pα and Pβ, with each subunit consisting of one catalytic and two GAF regions. A comparison of the average image of Pαβγγ with those of Pγ-released PDE suggests that Pγ release does not affect the overall structure of Pαβ, and that the Pαβ C-terminus, but not Pγ, is a determinant for the Pαβ orientation on carbon-coated grids. These observations suggest that the basic structure of PDE does not change during its regulation, which implies that Pαβ is regulated by its regional interaction with Pγ.

本文言語英語
ページ(範囲)27-38
ページ数12
ジャーナルJournal of structural biology
139
1
DOI
出版ステータス出版済み - 11 21 2002
外部発表はい

All Science Journal Classification (ASJC) codes

  • Structural Biology

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