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A conserved isoleucine maintains the inactive state of Bruton’s tyrosine kinase
Journal of Molecular Biology
  • Scott E. Boyken, Iowa State University
  • Nikita Chopra, Iowa State University
  • Qian Xie, Iowa State University
  • Raji E. Joseph, Iowa State University
  • Thomas E. Wales, Northeastern University
  • D. Bruce Fulton, Iowa State University
  • John R. Engen, Northeastern University
  • Robert L. Jernigan, Iowa State University
  • Amy H. Andreotti, Iowa State University
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Despite high homology among non-receptor tyrosine kinases, different kinase families employ a diverse array of regulatory mechanisms. For example, the catalytic kinase domains of the Tec family kinases are inactive without assembly of the adjacent regulatory domains, whereas the Src kinase domains are autoinhibited by the assembly of similar adjacent regulatory domains. Using molecular dynamic simulations, biochemical assays, and biophysical approaches, we have uncovered an isoleucine residue in the kinase domain of the Tec family member Btk that, when mutated to the closely related leucine, leads to a shift in the conformational equilibrium of the kinase domain toward the active state. The single amino acid mutation results in measureable catalytic activity for the Btk kinase domain in the absence of the regulatory domains. We suggest this isoleucine side chain in the Tec family kinases acts as a ‘wedge’ that restricts the conformational space available to key regions in the kinase domain, preventing activation until the kinase domain associates with its regulatory subunits and overcomes the energetic barrier to activation imposed by the isoleucine side chain.


This is a manuscript of an article published as Boyken, Scott E., Nikita Chopra, Qian Xie, Raji E. Joseph, Thomas E. Wales, D. Bruce Fulton, John R. Engen, Robert L. Jernigan, and Amy H. Andreotti. "A conserved isoleucine maintains the inactive state of Bruton's tyrosine kinase." Journal of molecular biology 426, no. 21 (2014): 3656-3669. doi: 10.1016/j.jmb.2014.08.018. Posted with permission.

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Creative Commons Attribution-Noncommercial-No Derivative Works 4.0
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Elsevier Ltd
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Scott E. Boyken, Nikita Chopra, Qian Xie, Raji E. Joseph, et al.. "A conserved isoleucine maintains the inactive state of Bruton’s tyrosine kinase" Journal of Molecular Biology Vol. 426 Iss. 21 (2014) p. 3656 - 3669
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