>TIGR00484 EF-G translation elongation factor G; InterPro: IPR004540 Translation elongation factors are responsible for two main processes during protein synthesis on the ribosome , , . EF1A (or EF-Tu) is responsible for the selection and binding of the cognate aminoacyl-tRNA to the A-site (acceptor site) of the ribosome. EF2 (or EF-G) is responsible for the translocation of the peptidyl-tRNA from the A-site to the P-site (peptidyl-tRNA site) of the ribosome, thereby freeing the A-site for the next aminoacyl-tRNA to bind. Elongation factors are responsible for achieving accuracy of translation and both EF1A and EF2 are remarkably conserved throughout evolution. EF-G is a large, five-domain GTPase that promotes the directional movement of mRNA and tRNAs on the ribosome in a GTP-dependent manner. Unlike other GTPases, but by analogy to the myosin motor, EF-G performs its function of powering translocation in the GDP-bound form; that is, in a kinetically stable ribosome-EF-G(GDP) complex formed by GTP hydrolysis on the ribosome. The complex undergoes an extensive structural rearrangement, in particular affecting the small ribosomal subunit, which leads to mRNA-tRNA movement. Domain 4, which extends from the 'body' of the EF-G molecule much like a lever arm, appears to be essential for the structural transition to take place. In a hypothetical model, GTP hydrolysis induces a conformational change in the G domain of EF-G, which affects the interactions with neighbouring domains within EF-G. The resulting rearrangement of the domains relative to each other generates conformational strain in the ribosome to which EF-G is fixed. Because of structural features of the tRNA-ribosome complex, this conformational strain results in directional tRNA-mRNA movement. The functional parallels between EF-G and motor proteins suggest that EF-G differs from classical G-proteins in that it functions as a force-generating mechanochemical device rather than a conformational switch . Every completed bacterial genome has at least one copy, but some species have additional EF-G-like proteins. The closest homolog to canonical (e.g. Escherichia coli) EF-G in the spirochetes clusters as if it is derived from mitochondrial forms, while a more distant second copy is also present. Synechocystis sp. (strain PCC 6803) has a few proteins more closely related to EF-G than to any other characterised protein. Two of these resemble E. coli EF-G more closely than does the best match from the spirochetes; it may be that both function as authentic EF-G. More information about these proteins can be found at Protein of the Month: Elongation Factors . ; GO: 0003746 translation elongation factor activity, 0005525 GTP binding, 0006414 translational elongation, 0005622 intracellular.

Probab=98.19  E-value=3e-06  Score=55.06  Aligned_cols=129  Identities=16%  Similarity=0.209  Sum_probs=86.2

Q ss_pred             HCCCCCCCEEEEECCCCCCHHHHHHHHH---CCCC-EEEECCCCCE-E-------EECCEEEEEEEEEEEEC------CC
Q ss_conf             5887668689997489988989999973---8973-7987388841-4-------52120266555678508------96
Q gi|254780484|r   23 LLPKAGPPEIAFSGRSNVGKSSLINILV---NRKN-LARTSNAPGR-T-------QHLNFFVPKDFSNLKNN------LP   84 (212)
Q Consensus        23 ~~P~~~~p~VaivG~~NvGKSSLiNaL~---g~~~-~a~~~~~p~t-t-------~~~~~~~~~~~~~~~~~------~~   84 (212)
T Consensus         4 ~~~~~~~RNiGI~AHIDaGKTT~~ERILFy~g~~HkIgE~~g~dG~a~MDwME~E~ERGITItSAAT~~~Wk~~~~~~~~   83 (705)
T TIGR00484         4 TTDLEKLRNIGISAHIDAGKTTTTERILFYTGRIHKIGEVHGKDGAATMDWMEQEKERGITITSAATTVEWKGMAKQYDH   83 (705)
T ss_pred             CCCHHHCCCCCEEEEECCCCCCCHHEEEECCCCCCCEEECCCCCCCEECCHHHHCCCCCEEEECHHCCHHHHHHHHCCCC
T ss_conf             56523305543278633887320101000137501000001678851123123003587142100110102101000140


Q ss_pred             EEEEEECCHHHHHHHHHHHHHHHHHHHHHHHHHHHHHCCCCCCCCCCCCCCHHHHHHHHHHCCCCCCCCCCCCCCCCCCH
Q ss_conf             49999760010111224478988889987777664200000112235788754545543210257532212222111102
Q gi|254780484|r   85 AMALVDMPGYGYARAPKKNVDSWGGLIVRYLSERSTLRCVYLLIDCRHGVKQIDQDVFSFLDKKAVSYQIVLTKIDKLSP  164 (212)
Q Consensus        85 ~~~~~DtpG~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~v~nK~D~~~~  164 (212)
T Consensus        84 ~~N~IDTPGHVDFT~EVERS-------------lRVLDGAv~V~~a~~GV~pQ~~TVwRQa~~Y~VPRi~FVNK~Dk~GA  150 (705)
T TIGR00484        84 RINIIDTPGHVDFTVEVERS-------------LRVLDGAVAVLDAVGGVQPQSETVWRQANKYEVPRIVFVNKMDKTGA  150 (705)
T ss_pred             EEEEEECCCCEEEEEEEEEH-------------HHHHHHHHHHHHHCCCCCCCHHHHHHHHHHCCCCEEEEEECCCCCCC
T ss_conf             37887378941257885201-------------22564566533302686641156776543268862899715564578