Biomaterial Database

Eukaryotic initiation factors eIF-2 and eIF-3: interactions, structure and localization in ribosomal initiation complexes. 1991

U A Bommer, and G Lutsch, and J Stahl, and H Bielka

Institute of Molecular Biology, Berlin-Buch, Germany.

More than ten different protein factors are involved in initiation of protein synthesis in eukaryotes. For binding of initiator tRNA and mRNA to the 40S ribosomal subunit, the initiation factors eIF-2 and eIF-3 are particularly important. They consist of several different subunits and form stable complexes with the 40S ribosomal subunit. The location of eIF-2 and eIF-3 in these complexes as well as the interactions of the individual components have been analyzed by biochemical methods and electron microscopy. The results obtained are summarized in this article, and a model is derived describing the spatial arrangement of eIF-2 and eIF-3 together with initiator tRNA and mRNA on the 40S subunit. Conclusions on the location of functionally important sites of eukaryotic small ribosomal subunits are discussed with regard to the respective location of these sites in the prokaryotic counterpart.

UI	MeSH Term	Description	Entries
D009711	Nucleotides	The monomeric units from which DNA or RNA polymers are constructed. They consist of a purine or pyrimidine base, a pentose sugar, and a phosphate group. (From King & Stansfield, A Dictionary of Genetics, 4th ed)	Nucleotide
D010448	Peptide Initiation Factors	Protein factors uniquely required during the initiation phase of protein synthesis in GENETIC TRANSLATION.	Initiation Factors,Initiation Factor,Factors, Peptide Initiation,Initiation Factors, Peptide
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D012269	Ribosomal Proteins	Proteins found in ribosomes. They are believed to have a catalytic function in reconstituting biologically active ribosomal subunits.	Proteins, Ribosomal,Ribosomal Protein,Protein, Ribosomal
D012270	Ribosomes	Multicomponent ribonucleoprotein structures found in the CYTOPLASM of all cells, and in MITOCHONDRIA, and PLASTIDS. They function in PROTEIN BIOSYNTHESIS via GENETIC TRANSLATION.	Ribosome
D012333	RNA, Messenger	RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.	Messenger RNA,Messenger RNA, Polyadenylated,Poly(A) Tail,Poly(A)+ RNA,Poly(A)+ mRNA,RNA, Messenger, Polyadenylated,RNA, Polyadenylated,mRNA,mRNA, Non-Polyadenylated,mRNA, Polyadenylated,Non-Polyadenylated mRNA,Poly(A) RNA,Polyadenylated mRNA,Non Polyadenylated mRNA,Polyadenylated Messenger RNA,Polyadenylated RNA,RNA, Polyadenylated Messenger,mRNA, Non Polyadenylated
D012343	RNA, Transfer	The small RNA molecules, 73-80 nucleotides long, that function during translation (TRANSLATION, GENETIC) to align AMINO ACIDS at the RIBOSOMES in a sequence determined by the mRNA (RNA, MESSENGER). There are about 30 different transfer RNAs. Each recognizes a specific CODON set on the mRNA through its own ANTICODON and as aminoacyl tRNAs (RNA, TRANSFER, AMINO ACYL), each carries a specific amino acid to the ribosome to add to the elongating peptide chains.	Suppressor Transfer RNA,Transfer RNA,tRNA,RNA, Transfer, Suppressor,Transfer RNA, Suppressor,RNA, Suppressor Transfer
D013329	Structure-Activity Relationship	The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.	Relationship, Structure-Activity,Relationships, Structure-Activity,Structure Activity Relationship,Structure-Activity Relationships
D015394	Molecular Structure	The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.	Structure, Molecular,Molecular Structures,Structures, Molecular
D015852	Eukaryotic Initiation Factor-2	Eukaryotic initiation factor of protein synthesis. In higher eukaryotes the factor consists of three subunits: alpha, beta, and gamma. As initiation proceeds, eIF-2 forms a ternary complex with Met-tRNAi and GTP.	EIF-2,Peptide Initiation Factor EIF-2,EIF-2 alpha,EIF-2 beta,EIF-2 gamma,EIF-2alpha,EIF-2beta,EIF-2gamma,EIF2,Eukaryotic Initiation Factor-2, alpha Subunit,Eukaryotic Initiation Factor-2, beta Subunit,Eukaryotic Initiation Factor-2, gamma Subunit,Eukaryotic Peptide Initiation Factor-2,EIF 2,EIF 2 alpha,EIF 2 beta,EIF 2 gamma,EIF 2alpha,EIF 2beta,EIF 2gamma,Eukaryotic Initiation Factor 2,Eukaryotic Initiation Factor 2, alpha Subunit,Eukaryotic Initiation Factor 2, beta Subunit,Eukaryotic Initiation Factor 2, gamma Subunit,Eukaryotic Peptide Initiation Factor 2,Initiation Factor-2, Eukaryotic,Peptide Initiation Factor EIF 2