>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=95.82  E-value=0.021  Score=34.40  Aligned_cols=129  Identities=25%  Similarity=0.326  Sum_probs=72.1

Q ss_pred             EEEEEECEEEEECCCCCCCEEEEEE---CCCCCHHHHHH---H-CCC-----EECCEE--------EEE------CCEEE
Q ss_conf             9976301124421677753035410---14540121211---0-000-----001026--------632------98689
Q gi|254780648|r  155 KLKLIADIGIIGLPNAGKSTFLASV---TRAKPKIADYP---F-TTL-----YPNLGI--------VKE------GYKEF  208 (335)
Q Consensus       155 elk~iaDVglVG~PNaGKSTLln~l---s~ak~kIa~yp---F-TT~-----~P~lGv--------v~~------~~~~~  208 (335)
T Consensus         6 ~~~~~RNiGI~AHIDaGKTT~~ERILFy~g~~HkIgE~~g~dG~a~MDwME~E~ERGITItSAAT~~~Wk~~~~~~~~~~   85 (705)
T TIGR00484         6 DLEKLRNIGISAHIDAGKTTTTERILFYTGRIHKIGEVHGKDGAATMDWMEQEKERGITITSAATTVEWKGMAKQYDHRI   85 (705)
T ss_pred             CHHHCCCCCEEEEECCCCCCCHHEEEECCCCCCCEEECCCCCCCEECCHHHHCCCCCEEEECHHCCHHHHHHHHCCCCEE
T ss_conf             52330554327863388732010100013750100000167885112312300358714210011010210100014037


Q ss_pred             EEECCCCCCCCCCCCCCCHHHHHHHHHHH----HHHHHHCCCCCCCHHHHHHHHHHHHHHHHHHHCCCCEEEEEECCCCC
Q ss_conf             98226421247311677512344333335----78875202222110134666789987776675059889999746589
Q gi|254780648|r  209 ILADIPGIIKNAHQGAGIGDRFLKHTERT----HVLLHIVSALEENVQAAYQCILDELSAYNSELRKKIEIVGLSQIDTV  284 (335)
Q Consensus       209 ~i~D~PGlIegA~~~~glG~~FLrhIer~----~vLl~VVD~s~~d~~~~~~~I~~EL~~y~~~L~~Kp~IIVlNKiDl~  284 (335)
T Consensus        86 N~IDTPGHV-----------DFT~EVERSlRVLDGAv~V~~a~~G-V~pQ~~TVwRQa~~Y~-----VPRi~FVNK~Dk~  148 (705)
T TIGR00484        86 NIIDTPGHV-----------DFTVEVERSLRVLDGAVAVLDAVGG-VQPQSETVWRQANKYE-----VPRIVFVNKMDKT  148 (705)
T ss_pred             EEEECCCCE-----------EEEEEEEEHHHHHHHHHHHHHHCCC-CCCCHHHHHHHHHHCC-----CCEEEEEECCCCC
T ss_conf             887378941-----------2578852012256456653330268-6641156776543268-----8628997155645


Q ss_pred             CHHHHHHHHHHHHHHCC
Q ss_conf             98899999999998629
Q gi|254780648|r  285 DSDTLARKKNELATQCG  301 (335)
Q Consensus       285 ~~e~~~~~~~~l~~~~~  301 (335)
T Consensus       149 GAnf-~~~~~~~~~rL~  164 (705)
T TIGR00484       149 GANF-LRVVNQLKSRLG  164 (705)
T ss_pred             CCCH-HHHHHHHHHHHC
T ss_conf             7878-899999998746