Structural Basis for Chk1 Inhibition by UCN-01*
- Baoguang ZhaotOaFNb,
- Michael J. BowertOcFNd,
- Patrick J. McDevitttOe,
- Huizhen ZhaotOf,
- Stephen T. DavistOg,
- Kyung O. JohansontOe,
- Susan M. GreentOf,
- Nestor O. ConchatOa and
- Bin-Bing S. ZhouFNdtOh,i
- From the Departments of tOaStructural Biology,tOcPhysical and Structural Chemistry, tOeProtein Biochemistry, tOfGene Expression Science, and tOhOncology Research, GlaxoSmithKline, King of Prussia, Pennsylvania 19406 and thetOgDepartment of High Through-put Biology, GlaxoSmithKline, Research Triangle Park, North Carolina 27709
Abstract
Chk1 is a serine-threonine kinase that plays an important role in the DNA damage response, including G2/M cell cycle control. UCN-01 (7-hydroxystaurosporine), currently in clinical trials, has recently been shown to be a potent Chk1 inhibitor that abrogates the G2/M checkpoint induced by DNA-damaging agents. To understand the structural basis of Chk1 inhibition by UCN-01, we determined the crystal structure of the Chk1 kinase domain in complex with UCN-01. Chk1 structures with staurosporine and its analog SB-218078 were also determined. All three compounds bind in the ATP-binding pocket of Chk1, producing only slight changes in the protein conformation. Selectivity of UCN-01 toward Chk1 over cyclin-dependent kinases can be explained by the presence of a hydroxyl group in the lactam moiety interacting with the ATP-binding pocket. Hydrophobic interactions and hydrogen-bonding interactions were observed in the structures between UCN-01 and the Chk1 kinase domain. The high structural complementarity of these interactions is consistent with the potency and selectivity of UCN-01.
Footnotes
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↵* The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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↵FNb To whom correspondence may be addressed: Dept. of Structural Biology, GlaxoSmithKline Pharmaceuticals, 709 Swedeland Rd., King of Prussia, PA 19406. E-mail: baoguang_zhao-1@gsk.com.
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↵FNd Current address: Incyte Genomics, Inc., Stine-Haskell Research Center, 1090 Elkon Rd., Newark, DE 19714.
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↵i To whom correspondence may be addressed: Incyte Genomics, Inc., Stine-Haskell Research Center, 1090 Elkon Rd., Newark, DE 19714. Tel.: 302-283-7813; Fax: 302-283-7859; E-mail: binbing_s_zhou@yahoo.com.
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Published, JBC Papers in Press, September 19, 2002, DOI 10.1074/jbc.M201233200
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↵2 R. Johanson and B. Zhou, unpublished results.
- Abbreviations:
- UCN-01
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7-hydroxystaurosporine
- CDKs
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cyclin-dependent kinases
- AEBSF
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4-(2-Aminoethyl)benzenesulfonyl fluoride
- DTT
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dithiothreitol
- GST
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glutathione S-transferase
- AMP-PNP
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adenosine 5′-(β,γ-imino)triphosphate
- r.m.s.
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root mean square
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- Received February 6, 2002.
- Revision received September 19, 2002.
- The American Society for Biochemistry and Molecular Biology, Inc.
