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KMID : 0613820080180040585
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Journal of Life Science
2008 Volume.18 No. 4 p.585 ~ p.589
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Closed Conformation of a Human Phosphatase, Chronophin under the Reduced Condition
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Cho Hyo-Je
Kang Beom-Sik
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Abstract
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Chronophin is a phosphatase responsible for the dephosphorylation of cofilin, which regulates the rearrangement of actin cytoskeleton. It is also known as a phosphatase for pyrodoxal 5’-phosphate (PLP), an active form of vitamin B6, and maintains the level of PLP in the cytoplasm. Since this phosphatase belongs to a HAD subfamily containing a cap domain, it is expected to undergo a conformational change for the binding of a substrate. However, the crystal structure of chronophin has a disulfide bridge between the cap and core domains preventing a movement of the cap domain against the core domain. It is possible that the disulfide bond between C91 and C221 was formed by an oxidation during the crystallization. Here, we obtained chronophin crystals under a reduced condition and determined the crystal structure. This reduced chronophin does not contain a disulfide bridge and shows a closed conformation like the oxidized form. It implies that an active chronophin binds its substrate under the closed conformation without the disulfide bond and shows a high substrate specificity in the cell.
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KEYWORD
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Chronophin, phosphatase, disulfide bond, crystal structure
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