An N-Terminal Extension to UBA5 Adenylation Domain Boosts UFM1 Activation: Isoform-Specific Differences in Ubiquitin-like Protein Activation

JOURNAL OF MOLECULAR BIOLOGY

卷:431

Article

Soudah, Nadine¹  Padala, Prasanth¹  Hassouna, Fouad¹  Kumar, Manoj¹  Mashahreh, Bayan¹  Lebedev, Andrey A.²  Isupov, Michail N.³  Cohen-Kfir, Einav¹  Wiener, Reuven¹ 

[1] Hebrew Univ Jerusalem, Hadassah Med Sch, Inst Med Res Israel Canada, Dept Biochem & Mol Biol, IL-91120 Jerusalem, Israel

[2] STFC Rutherford Appleton Lab, Res Complex Harwell, CCP4, Didcot OX11 0FA, Oxon, England

[3] Univ Exeter, Henry Wellcome Bldg Biocatalysis, Biosci, Stocker Rd, Exeter EX4 4QD, Devon, England

关键词: UFM1;    UBA5;    ubiquitin-like proteins;    E1 activating enzymes;    crystal structure;   

DOI  :  10.1016/j.jmb.2018.10.007

来源: Elsevier

【 摘 要 】

Modification of proteins by the ubiquitin-like protein, UFM1, requires activation of UFM1 by the E1 activating enzyme, UBA5. In humans, UBA5 possesses two isoforms, each comprising an adenylation domain, but only one containing an N-terminal extension. Currently, the role of the N-terminal extension in UFM1 activation is not clear. Here we provide structural and biochemical data on UBA5 N-terminal extension to understand its contribution to UFM1 activation. The crystal structures of the UBA5 long isoform bound to ATP with and without UFM1 show that the N-terminus not only is directly involved in ATP binding but also affects how the adenylation domain interacts with ATP. Surprisingly, in the presence of the N-terminus, UBA5 no longer retains the 1:2 ratio of ATP to UBA5, but rather this becomes a 1:1 ratio. Accordingly, the N-terminus significantly increases the affinity of ATP to UBA5. Finally, the N-terminus, although not directly involved in the E2 binding, stimulates transfer of UFM1 from UBA5 to the E2, UFC1. 2018 Elsevier Ltd. All rights reserved.

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