Ravi K Koripella / Manjuli R Sharma / Md Emdadul Haque / Paul Risteff / Linda L Spremulli / Rajendra K Agrawal /
PubMed 要旨
The human mitochondrial translational initiation factor 3 (IF3) carries mitochondrial-specific amino acid extensions at both its N and C termini (N- and C-terminal extensions [NTE and CTE, ...The human mitochondrial translational initiation factor 3 (IF3) carries mitochondrial-specific amino acid extensions at both its N and C termini (N- and C-terminal extensions [NTE and CTE, respectively]), when compared with its eubacterial counterpart. Here we present 3.3- to 3.5-Å-resolution cryoelectron microscopic structures of the mammalian 28S mitoribosomal subunit in complex with human IF3. Unique contacts observed between the 28S subunit and N-terminal domain of IF3 explain its unusually high affinity for the 28S subunit, whereas the position of the mito-specific NTE suggests NTE's role in binding of initiator tRNA to the 28S subunit. The location of the C-terminal domain (CTD) clarifies its anti-association activity, whereas the orientation of the mito-specific CTE provides a mechanistic explanation for its role in destabilizing initiator tRNA in the absence of mRNA. Furthermore, our structure hints at a possible role of the CTD in recruiting leaderless mRNAs for translation initiation. Our findings highlight unique features of IF3 in mitochondrial translation initiation.
EMDB-9358, PDB-6neq: Structure of human mitochondrial translation initiation factor 3 bound to the small ribosomal subunit-Class-II 手法: EM (単粒子) / 解像度: 3.32 Å
EMDB-9362: Structure of human mitochondrial translation initiation factor 3 bound to the small ribosomal subunit PDB-6nf8: Structure of human mitochondrial translation initiation factor 3 bound to the small ribosomal subunit -Class I 手法: EM (単粒子) / 解像度: 3.48 Å
由来
homo sapiens (ヒト)
Bovine (ウシ)
bos taurus (ウシ)
Human (ヒト)
キーワード
RIBOSOMAL PROTEIN / Human mitochondrial translation Initiation Factor 3 / Mitochondrial translation Initiation Factor 3