Solution structure of lysine-free (K0) ubiquitin

Authors

  • Tao Huang,

    1. Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland
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  • Jess Li,

    1. Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland
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  • R. Andrew Byrd

    Corresponding author
    1. Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, Maryland
    • Correspondence to: R. Andrew Byrd; Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702. E-mail: byrdra@mail.nih.gov

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Abstract

Lysine-free ubiquitin (K0-Ub) is commonly used to study the ubiquitin-signaling pathway, where it is assumed to have the same structure and function as wild-type ubiquitin (wt-Ub). However, the K0-Ub 15N heteronuclear single quantum correlation NMR spectrum differs significantly from wt-Ub and the melting temperature is depressed by 19°C, raising the question of the structural integrity and equivalence to wt-Ub. The three-dimensional structure of K0-Ub was determined by solution NMR, using chemical shift and residual dipolar coupling data. K0-Ub adopts the same backbone structure as wt-Ub, and all significant chemical shifts can be related to interactions impacted by the K to R mutations.

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