Domain II of the gamma subunit of eukaryotic translation initiation factor 2; This subfamily represents domain II of the gamma subunit of eukaryotic translation initiation factor 2 (eIF2-gamma) found in eukaryota and archaea. eIF2 is a G protein that delivers the methionyl initiator tRNA to the small ribosomal subunit and releases it upon GTP hydrolysis after the recognition of the initiation codon. eIF2 is composed of three subunits, alpha, beta and gamma. Subunit gamma shows strongest conservation, and it confers both tRNA binding and GTP/GDP binding.

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gi 1940753924  29 DLTAYLRLIVIRSFDV-KPGAEADSLTRGIGGCSILSGASKLRDKIEIRPGIVTKDnEGKIK 89
Cdd:cd03688     1 DLDKPPRMIVIRSFDVnKPGTEVDDLKGGVIGGSLIQGVLKVGDEIEIRPGIVVKK-GGKTT 61

translation initiation factor IF-2 subunit gamma; Validated

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1940753924   2 VPISAQFKCNIDTVNKYIDKRILIPIRDLTAYLRLIVIRSFDV-KPGAEADSLTRGIGGCSILSGASKLRDKIEIRPGIV 80
Cdd:PRK04000  179 IPVSALHKVNIDALIEAIEEEIPTPERDLDKPPRMYVARSFDVnKPGTPPEKLKGGVIGGSLIQGVLKVGDEIEIRPGIK 258

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gi 1940753924  81 TKDnEGKIK 89
Cdd:PRK04000  259 VEE-GGKTK 266

Gamma subunit of initiation factor 2 (eIF2 gamma); eIF2 is a heterotrimeric translation initiation factor that consists of alpha, beta, and gamma subunits. The GTP-bound gamma subunit also binds initiator methionyl-tRNA and delivers it to the 40S ribosomal subunit. Following hydrolysis of GTP to GDP, eIF2:GDP is released from the ribosome. The gamma subunit has no intrinsic GTPase activity, but is stimulated by the GTPase activating protein (GAP) eIF5, and GDP/GTP exchange is stimulated by the guanine nucleotide exchange factor (GEF) eIF2B. eIF2B is a heteropentamer, and the epsilon chain binds eIF2. Both eIF5 and eIF2B-epsilon are known to bind strongly to eIF2-beta, but have also been shown to bind directly to eIF2-gamma. It is possible that eIF2-beta serves simply as a high-affinity docking site for eIF5 and eIF2B-epsilon, or that eIF2-beta serves a regulatory role. eIF2-gamma is found only in eukaryotes and archaea. It is closely related to SelB, the selenocysteine-specific elongation factor from eubacteria. The translational factor components of the ternary complex, IF2 in eubacteria and eIF2 in eukaryotes are not the same protein (despite their unfortunately similar names). Both factors are GTPases; however, eubacterial IF-2 is a single polypeptide, while eIF2 is heterotrimeric. eIF2-gamma is a member of the same family as eubacterial IF2, but the two proteins are only distantly related. This family includes translation initiation, elongation, and release factors.

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gi 1940753924   2 VPISAQFKCNIDTVNKYIDKRILIPIR 28
Cdd:cd01888   171 IPISAQLKYNIDVLCEYIVKKIPTPPR 197