>TIGR00392 ileS isoleucyl-tRNA synthetase; InterPro: IPR002301 The aminoacyl-tRNA synthetases (6.1.1. from EC) catalyse the attachment of an amino acid to its cognate transfer RNA molecule in a highly specific two-step reaction. These proteins differ widely in size and oligomeric state, and have limited sequence homology . The 20 aminoacyl-tRNA synthetases are divided into two classes, I and II. Class I aminoacyl-tRNA synthetases contain a characteristic Rossman fold catalytic domain and are mostly monomeric . Class II aminoacyl-tRNA synthetases share an anti-parallel beta-sheet fold flanked by alpha-helices , and are mostly dimeric or multimeric, containing at least three conserved regions , , . However, tRNA binding involves an alpha-helical structure that is conserved between class I and class II synthetases. In reactions catalysed by the class I aminoacyl-tRNA synthetases, the aminoacyl group is coupled to the 2'-hydroxyl of the tRNA, while, in class II reactions, the 3'-hydroxyl site is preferred. The synthetases specific for arginine, cysteine, glutamic acid, glutamine, isoleucine, leucine, methionine, tyrosine, tryptophan and valine belong to class I synthetases; these synthetases are further divided into three subclasses, a, b and c, according to sequence homology. The synthetases specific for alanine, asparagine, aspartic acid, glycine, histidine, lysine, phenylalanine, proline, serine, and threonine belong to class-II synthetases . Isoleucyl-tRNA synthetase (6.1.1.5 from EC) is an alpha monomer that belongs to class Ia. The enzyme, isoleucyl-transfer RNA synthetase, activates not only the cognate substrate L-isoleucine but also the minimally distinct L-valine in the first, aminoacylation step. Then, in a second, "editing" step, the synthetase itself rapidly hydrolyzes only the valylated products , as shown from the crystal structures. ; GO: 0000166 nucleotide binding, 0004822 isoleucine-tRNA ligase activity, 0005524 ATP binding, 0006412 translation, 0006428 isoleucyl-tRNA aminoacylation, 0005737 cytoplasm.

Probab=99.00 E-value=3.4e-08 Score=76.41 Aligned_cols=249 Identities=18% Similarity=0.188 Sum_probs=158.8 Q ss_pred CCEECHHHHHH--CCHHHHHHHHHHHH-HCCCCC--CCCCCCCCCCCCCCC---------CCCCCCEEEEHHHCCCCCCC Q ss_conf 10001588730--10457999999999-749851--134267555654200---------02478156510110222222 Q gi|254780285|r 257 DIFISEDDFHR--GDPSPIRDIIDNLA-RQGYVY--EGILPPPKSKTTQKC---------DMDRKQLLFRSTMVGDDVDR 322 (586) Q Consensus 257 D~~~~Es~~~~--~~~~~i~~~i~~l~-~~g~~~--e~~~~~~~~~~~~~~---------~~~~~~~~~~~~~~g~~~d~ 322 (586) T Consensus 528 P~w~~e~~~~~~l~~~gsi~el~~~~~~~~G~~~w~~d~~~~~~d~~~~~~~~g~~~y~r~~DvlDVWFDS--------- 598 (938) T TIGR00392 528 PVWYCEDTGEPVLIVVGSIEELEELIEVEKGIDAWFEDLHKDLLDKITLESGSGGGEYRRVPDVLDVWFDS--------- 598 (938) T ss_pred EEEEECCCCCEEEEEECCHHHHHHHHHHHHCCCCCCCCCCCCCCCCCCCCCCCCCCCEEEECEEEEEECCC--------- T ss_conf 06886678832677604089999999987256632223444457741345889984258712155451140--------- Q ss_pred CCCCCCCCHHHHHHHHHHHHHHHHC--CCCCCCCCCCCCH-HHHHHHHHHHHHHHC--CCCCCCEEEECCHHHCCCCCCC Q ss_conf 2102465213568889999997522--5554333677761-368999999999722--6634511531101101221100 Q gi|254780285|r 323 PLLKSDGSYTYFAADLAYFKCKYER--GFDNMIYVMGSDH-SGYVKRLEAVAAAVS--EKKAQINVLLCELVRLYRDGMP 397 (586) Q Consensus 323 vl~rsDGt~~Y~t~DiA~~~~k~e~--~~d~~iyVv~~~Q-~~h~~~v~~~~~~lg--~~~~~~~~~~~~~v~l~~dg~~ 397 (586) T Consensus 599 ------Gs~~~A~~~~~~~~~~~~~~~pAD--~i~EG~DQ~RGWFySsl~~~~~~~nv~~~PYK~Vi~hGF~-LDe~G~- 668 (938) T TIGR00392 599 ------GSMPYAVLHYPFENEKFKEVFPAD--FILEGSDQTRGWFYSSLLIGVALFNVGKAPYKNVITHGFT-LDEKGR- 668 (938) T ss_pred ------CHHHHHHHHCCCCCHHHCCCCCCE--EEEECCCCCCHHHHHHHHHHHHHHCCCCCCCCEEEECCEE-ECCCCC- T ss_conf ------011799863232100103578302--6860335553277999999999870788543634531548-857785- Q ss_pred CCCCCCCCCHHHHHHHHH--------HHHHHHHHHHHHHH--CCHHHHHHHHHHHHHHCCCCHHHHHHHHHHH-HH--HH Q ss_conf 000122330245677777--------63211234555420--0012333447776532024436788888888-99--99 Q gi|254780285|r 398 IKMSKRAGDFITLRHVVD--------EVGSDSVRFMMLWR--KNSELLDFDFCKVKEQSKENPVFYVQYAYAR-CR--SI 464 (586) Q Consensus 398 ~kmstR~G~~v~l~dll~--------evg~~aiky~~L~~--~~~~~~~Fd~d~~l~~~~~nt~~YiqYa~aR-~~--SI 464 (586) T Consensus 669 -KMSKSlGNvV~P~~v~~G~~N~~~P~yGAD~LRlyv~~~P~~~~~Dl~~~~~~~~~v~-~-~~~~~~~N~~~Fl~~Yan 745 (938) T TIGR00392 669 -KMSKSLGNVVDPEKVINGDENLKLPKYGADILRLYVASSPSDYWEDLRFSDEILKQVA-E-KYRKIRWNTYRFLLTYAN 745 (938) T ss_pred -CCCCCCCCCCCHHHHCCCCCCCCCCCCCCHHHHHHHHHCCCCCHHCCCCCHHHHHHHH-H-HHHHHHHHHHHHHHHHHH T ss_conf -4453258703859970884335887533048777788468740002200668999999-9-876889999999999887 Q ss_pred HHHHHHHCCCCCCCCCCCCCCCCCCCCCHHHHHHHHHHHHHHHHHHHHHHHCCCHHHHHHHHHHHHH-HHHHHHH Q ss_conf 8753320024683223422355211499899999999842189999999852812799999999998-8999870 Q gi|254780285|r 465 FRQAKDIFPDLDFDLFPRNVIPQESEFDTSELQLIVHLAEYPRVIENATIAQEPYKLAFYLYDLASV-FHGHWSH 538 (586) Q Consensus 465 lrKa~~~~~~~~~~~~~~~~~~~~~~~~~~E~~L~~~l~~f~~vi~~a~~~~~P~~l~~Yl~~La~~-Fn~fY~~ 538 (586) T Consensus 746 L~~f~p~~~~~-----------~~~~~~~~Drw~L~~l~~l~~~v~~~~e~Y~f~~~~~~l~~F~~~~LS~wY~~ 809 (938) T TIGR00392 746 LDKFDPEEKAV-----------AVEKFRELDRWILSRLNSLVEEVNEALEKYNFHKVLRALQDFIVEELSNWYIR 809 (938) T ss_pred HHCCCCCCCCC-----------CHHCCCHHHHHHHHHHHHHHHHHHHHHHCCCHHHHHHHHHHHHHHHCCHHHHH T ss_conf 60778730023-----------11203011399999999999999998626324678888987631200045666

HHsearch alignment for GI: 254780285 and conserved domain: TIGR00392