Protein synthesis in eukaryotic cell is spatially and structurally compartmentalized that ensures high efficiency of this process. One of the distinctive features of higher eukaryotes is the existence of stable multi-protein complexes of aminoacyl-tRNA synthetases and translation elongation factors. Here, we report a quaternary organization of the human guanine-nucleotide exchange factor (GEF) complex, eEF1B, comprising α, β and γ subunits that specifically associate into a heterotrimeric form eEF1B(αβγ)3. As both the eEF1Bα and eEF1Bβ proteins have structurally conserved GEF domains, their total number within the complex is equal to six. Such, so far, unique structural assembly of the guanine-nucleotide exchange factors within a stable complex may be considered as a ‘GEF hub’ that ensures efficient maintenance of the translationally active GTP-bound conformation of eEF1A in higher eukaryotes.

Endothelial and monocyte-activating polypeptide II (EMAP II) is a cytokine that plays an important role in inflammation, apoptosis and angiogenesis processes in tumour tissues. Structurally, the EMAP II is a 169 amino acid residues long C-terminal domain (residues 147-312) of auxiliary tRNA binding protein p43. In spite of existence in pdb databank of two X-ray structures there are some important aspects of EMAP II cytokine function which are still not fully understood in detail. To obtain information about 3D structure and backbone dynamic processes in solution we perform structure evaluation of human EMAP II cytokine by NMR spectroscopy. The standard approach to sequence-specific backbone assignment using 3D NMR data sets was not successful in our studies and was supplemented by recently developed 4D NMR experiments with random sampling of evolution time space. Here we report the backbone and side chain (1)H, (13)C, and (15)N chemical shifts in solution for recombinant EMAP II cytokine together with secondary structure provided by TALOS + software.

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