NMR and X-RAY structures of human E2-like ubiquitin-fold modifier conjugating enzyme 1 (UFC1) reveal structural and functional conservation in the metazoan UFM1-UBA5-UFC1 ubiquination pathway.
For cell regulation, E2-like ubiquitin-fold modifier conjugating enzyme 1 (Ufc1) is involved in the transfer of ubiquitin-fold modifier 1 (Ufm1), a ubiquitin like protein which is activated by E1-like enzyme Uba5, to various target proteins. Thereby, Ufc1 participates in the very recently discovered Ufm1-Uba5-Ufc1 ubiquination pathway which is found in metazoan organisms. The structure of human Ufc1 was solved by using both NMR spectroscopy and X-ray crystallography. The complementary insights obtained with the two techniques provided a unique basis for understanding the function of Ufc1 at atomic resolution. The Ufc1 structure consists of the catalytic core domain conserved in all E2-like enzymes and an additional N-terminal helix. The active site Cys(116), which forms a thio-ester bond with Ufm1, is located in a flexible loop that is highly solvent accessible. Based on the Ufc1 and Ufm1 NMR structures, a model could be derived for the Ufc1-Ufm1 complex in which the C-terminal Gly(83) of Ufm1 may well form the expected thio-ester with Cys(116), suggesting that Ufm1-Ufc1 functions as described for other E1-E2-E3 machineries. alpha-helix 1 of Ufc1 adopts different conformations in the crystal and in solution, suggesting that this helix plays a key role to mediate specificity.
Liu
Gaohua
G
Department of Chemistry, Northeast Structural Genomics Consortium, The State University of New York at Buffalo, Buffalo, NY 14260, USA.
Forouhar
Farhad
F
Eletsky
Alexander
A
Atreya
Hanudatta S
HS
Aramini
James M
JM
Xiao
Rong
R
Huang
Yuanpeng J
YJ
Abashidze
Mariam
M
Seetharaman
Jayaraman
J
Liu
Jinfeng
J
Rost
Burkhard
B
Acton
Thomas
T
Montelione
Gaetano T
GT
Hunt
John F
JF
Szyperski
Thomas
T
D000818:Animals; D018360:Crystallography, X-Ray; D006801:Humans; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D011487:Protein Conformation; D017510:Protein Folding; D044764:Ubiquitin-Activating Enzymes / Q000737:chemistry; D044763:Ubiquitin-Conjugating Enzymes / Q000737:chemistry*; D014452:Ubiquitins / Q000737:chemistry*
C502096:UFC1 protein, human; D014452:Ubiquitins; D044763:Ubiquitin-Conjugating Enzymes; D044764:Ubiquitin-Activating Enzymes