Translation initiation factor eIF1A possesses RNA annealing activity in its oligonucleotide-binding fold.
Translation initiation factor eIF1A is highly conserved among all eukaryotes, and performs essential functions in the formation of 43S preinitiation complex and mRNA scanning. In this study, we found that RNA annealing activity is intrinsically associated with eIF1A. Schizosaccharomyces pombe, Saccharomyces cerevisiae, and human eIF1As were isolated in their recombinant forms in order to determine their RNA annealing activities. A truncated eIF1A devoid of both N- and C-terminal domains proved most active, indicating that the activity is localized in the OB-fold domain. Some N- or C-terminal His tag fusions were shown to make the proteins inactive. This is probably caused by shielding of the RNA binding surface, as the proteins were activated via partial proteolytic digestion. We also found that eIF1A formed a stable complex with a short double-stranded RNA in gel mobility shift assays. Our results indicate that eIF1A may function as an RNA chaperone, inducing conformational changes in rRNA in the 43S preinitiation complex.
Kwon
Sung-Hun
SH
Department of Biological Sciences, College of Natural Science, Inha University, 253 Yonghyun-dong, Nam-gu, Incheon 402-751, Republic of Korea.
Lee
In-Hwan
IH
Kim
Na-Yeon
NY
Choi
Do-Hee
DH
Oh
Young-Mi
YM
Bae
Sung-Ho
SH
D001665:Binding Sites; D024202:Electrophoretic Mobility Shift Assay; D015977:Eukaryotic Initiation Factor-1 / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D009843:Oligoribonucleotides / Q000737:chemistry / Q000378:metabolism*; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D012313:RNA / Q000378:metabolism*; D012330:RNA, Double-Stranded / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D012568:Schizosaccharomyces / Q000378:metabolism
D015977:Eukaryotic Initiation Factor-1; D009843:Oligoribonucleotides; D012330:RNA, Double-Stranded; D011994:Recombinant Proteins; C026022:eukaryotic peptide initiation factor-1A; D012313:RNA