title: Conformational transitions in the γ subunit of the archaeal translation initiation factor 2.
abstract: In eukaryotes and archaea, the heterotrimeric translation initiation factor 2 (e/aIF2) is pivotal for the delivery of methionylated initiator tRNA (Met-tRNA(i)) to the ribosome. It acts as a molecular switch that cycles between inactive (GDP-bound) and active (GTP-bound) states. Recent studies show that eIF2 can also exist in a long-lived eIF2γ-GDP-P(i) (inorganic phosphate) active state. Here, four high-resolution crystal structures of aIF2γ from Sulfolobus solfataricus are reported: aIF2γ-GDPCP (a nonhydrolyzable GTP analogue), aIF2γ-GDP-formate (in which a formate ion possibly mimics P(i)), aIF2γ-GDP and nucleotide-free aIF2γ. The structures describe the different states of aIF2γ and demonstrate the conformational transitions that take place in the aIF2γ `life cycle'.
authors.affiliation: Institute of Protein Research, Russian Academy of Sciences, Pushchino 142290, Moscow Region, Russian Federation.
authors.forename: Oleg
authors.initials: O
authors.lastname: Nikonov
authors.affiliation: Institute of Protein Research, Russian Academy of Sciences, Pushchino 142290, Moscow Region, Russian Federation.
authors.forename: Elena
authors.initials: E
authors.lastname: Stolboushkina
authors.affiliation: Institute of Protein Research, Russian Academy of Sciences, Pushchino 142290, Moscow Region, Russian Federation.
authors.forename: Valentina
authors.initials: V
authors.lastname: Arkhipova
authors.affiliation: Institute of Protein Research, Russian Academy of Sciences, Pushchino 142290, Moscow Region, Russian Federation.
authors.forename: Olesya
authors.initials: O
authors.lastname: Kravchenko
authors.affiliation: Institute of Protein Research, Russian Academy of Sciences, Pushchino 142290, Moscow Region, Russian Federation.
authors.forename: Stanislav
authors.initials: S
authors.lastname: Nikonov
authors.affiliation: Institute of Protein Research, Russian Academy of Sciences, Pushchino 142290, Moscow Region, Russian Federation.
authors.forename: Maria
authors.initials: M
authors.lastname: Garber
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry* / Q000235:genetics; D018360:Crystallography, X-Ray; D006160:Guanosine Triphosphate / Q000737:chemistry; D010448:Peptide Initiation Factors / Q000737:chemistry* / Q000235:genetics; D011487:Protein Conformation; D021122:Protein Subunits / Q000737:chemistry* / Q000235:genetics; D048229:Sulfolobus solfataricus / Q000737:chemistry* / Q000235:genetics
chemical_list: D019843:Archaeal Proteins; D010448:Peptide Initiation Factors; D021122:Protein Subunits; C116557:initiation factor 2, archaeal; D006160:Guanosine Triphosphate
keywords: GTP-binding proteins; Sulfolobus solfataricus; translation initiation factor 2