title: Crystal structure of human eIF3k, the first structure of eIF3 subunits.
abstract: eIF3k, the smallest subunit of eukaryotic initiation factor 3 (eIF3), interacts with several other subunits of eIF3 and the 40 S ribosomal subunit. eIF3k is conserved among high eukaryotes, including mammals, insects, and plants, and it is ubiquitously expressed in human tissues. Interestingly, eIF3k does not exist in some species of yeast. Thus, eIF3k may play a unique regulatory role in higher organisms. Here we report the crystal structure of human eIF3k, the first high-resolution structure of an eIF3 component. This novel structure contains two distinct domains, a HEAT (named for Huntington, elongation factor 3, A subunit of protein phosphatase 2A, target of rapamycin) repeat-like HAM (HEAT analogous motif) domain and a winged-helix-like WH domain. Through structural comparison and sequence conservation analysis, we show that eIF3k has three putative protein-binding surfaces and has potential RNA binding activity. The structure provides key information for understanding the structure and function of the eIF3 complex.
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, People's Republic of China.
authors.forename: Zhiyi
authors.initials: Z
authors.lastname: Wei
authors.forename: Ping
authors.initials: P
authors.lastname: Zhang
authors.forename: Zhaocai
authors.initials: Z
authors.lastname: Zhou
authors.forename: Zhongjun
authors.initials: Z
authors.lastname: Cheng
authors.forename: Mao
authors.initials: M
authors.lastname: Wan
authors.forename: Weimin
authors.initials: W
authors.lastname: Gong
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000378:metabolism; D018360:Crystallography, X-Ray; D018076:DNA, Complementary / Q000378:metabolism; D039621:Eukaryotic Initiation Factor-3 / Q000737:chemistry*; D015723:Gene Library; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid
chemical_list: D018076:DNA, Complementary; C468124:EIF3K protein, human; D039621:Eukaryotic Initiation Factor-3; D008869:Microtubule-Associated Proteins