>TIGR00418 thrS threonyl-tRNA synthetase; InterPro: IPR002320 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 . Threonyl-tRNA synthetase (6.1.1.3 from EC) exists as a monomer and belongs to class IIa. The enzyme from Escherichia coli represses the translation of its own mRNA. The crystal structure of the complex between tRNA(Thr) and ThrRS show structural features that reveal novel strategies for providing specificity in tRNA selection. These include an amino-terminal domain containing a novel protein fold that makes minor groove contacts with the tRNA acceptor stem. The enzyme induces a large deformation of the anticodon loop, resulting in an interaction between two adjacent anticodon bases, which accounts for their prominent role in tRNA identity and translational regulation. A zinc ion found in the active site is implicated in amino acid recognition/discrimination . The zinc ion may act to ensure that only amino acids that possess a hydroxyl group attached to the beta-position are activated .; GO: 0004829 threonine-tRNA ligase activity, 0005524 ATP binding, 0006412 translation, 0006435 threonyl-tRNA aminoacylation, 0005737 cytoplasm.

Probab=100.00 E-value=0 Score=1445.19 Aligned_cols=561 Identities=48% Similarity=0.900 Sum_probs=545.1 Q ss_pred HHHHHHHHHHHHHHHCCCCEEEEECCCCCCEEEEEECCCCCCHHHHHHHHHHHHHHHHCCCCEEEEECCHHHHHHHHHHC Q ss_conf 99899999999999779988997243588557884088888898999999999999966998048532767854454416 Q gi|254781004|r 74 RHSCAHIMAEAVQSIWPEVQVAIGPIIEDGFYYDFDKEQPFSSDELAQIEKKMQEIIARDSPFLKQYLSHEKARELFESK 153 (652) Q Consensus 74 ~hS~ahlL~~Av~~l~p~~kl~igp~i~~GfYyD~~~~~~it~~dl~~Ie~~M~~ii~~~~pi~r~~vs~~eA~~~F~~~ 153 (652) T Consensus 1 rh~~Ah~l~~a~k~~~~~~~~~~gp~~e~GFyyD~~~~~~~~~~dl~~ie~~m~~~~~~~~~~~~~~~s~~~A~~~f~~~ 80 (595) T TIGR00418 1 RHSIAHLLAEAVKQLYPDVKLAVGPVIEDGFYYDFEVDKSITEEDLEKIEKEMKEIIKKNYPIARLSVSLEEALEAFKEV 80 (595) T ss_pred CCCHHHHHHHHHHHCCCCCEEEEECCCCCCCCCCCCCCHHCCHHHHHHHHHHHHHHHHHHCCEEEEEECHHHHHHHHHHH T ss_conf 95012463899970478718998255478754552000002778999999999999864057025772478999999862 Q ss_pred CCHHHHHHHHH-CCCCCCCEEECCCC-CEEECCCCCCCHHHHHH---HHHHHHHHHHHCCCCCCCCCEEEEEEE----EE Q ss_conf 71135566542-03455421302575-20100023552144422---233333321110157756420689999----98 Q gi|254781004|r 154 KEAYKVEILES-IPAKENVTLYRQGE-WFDLCRGPHVRSTGQVK---KFFKLMKVAGAYWRGDSNRPMLSRIYG----TA 224 (652) Q Consensus 154 ~~~~K~~li~~-~~~~~~v~~y~~g~-~~Dlc~GphvpsTg~ik---~~fkL~~~sgayw~gd~~~~~l~Riyg----~a 224 (652) T Consensus 81 ~~~~k~~l~~~~~~~~~~~~~y~~~~~f~dlC~GpHlp~~~~~~~~~~~fkL~~~~gaYw~Gd~~n~~LqRiyGn~~~~~ 160 (595) T TIGR00418 81 GEPLKLELLDEIIPNGEAVTVYGQGEAFVDLCRGPHLPNTSRIKPAQKAFKLEKVAGAYWRGDSKNEMLQRIYGNIDITA 160 (595) T ss_pred CCHHHHHHHHHCCCCCCCEEEECCCCEEEECCCCCCCCCCCCCCCCCHHHHHHHHHHHHHCCCCCCCEEEEECCCEEEEC T ss_conf 13122677851045666420422521345615797683235667640345665432331026889853788857254501 Q ss_pred ECCHHHHHHHHHHHHHHHHH--HHHHHHHHCCEEEECC-CCCCEEEEECCHHHHHHHHHHHHHHHH-HCCCEEEECCCCC Q ss_conf 37988999999999975320--0887541144044226-787435650107899999999999887-6896385554324 Q gi|254781004|r 225 WNTQQELTQYLYFLEESEKR--DHRKLAREMDLFHIAE-DGSGVIFWHRKGWKIFQTLISYMRRKI-KDDYEEINTPQVL 300 (652) Q Consensus 225 f~~~~~l~~~~~~~eea~~r--dHr~lg~~~~lf~~~~-~~~G~~~wlP~G~~i~~~ie~~ir~~~-~~G~~eV~tP~l~ 300 (652) T Consensus 161 ~~~k~~L~~yl~~~eEa~~r~PDHRklGKeL~Lf~f~~~~gpG~~~WlPkG~~ir~~ledf~~~~~~~~Gy~~V~TP~m~ 240 (595) T TIGR00418 161 FADKKQLAEYLKRLEEAKKREPDHRKLGKELELFSFEPEIGPGLPFWLPKGALIRNLLEDFVREKQIKRGYEEVETPIMY 240 (595) T ss_pred CCCHHHHHHHHHHHHHHHCCCCCHHHHHHHHCCCCCCCCCCCCCEEECCCHHHHHHHHHHHHHHHHHHCCCCCCCCCEEC T ss_conf 45878999999999997426857256754531234583204874146576467899999999999987588641574121 Q ss_pred CCCCCCCCCCCCCCCCCCCEEECCCCCCCCCCEEEECCCCHHHHHHHHHHCCCCHHHCCHHHHHHE-EEECCCCCCCCEE Q ss_conf 431000112100125554201001456777823774343125777765201222231043200010-0012787645200 Q gi|254781004|r 301 DQHLWQQSGHWDSYRANMFAVKCADDTIKDLRTFALKPMNCPGHVAVFNHGLKSYRELPVRLAEFG-SVYRNEPSGSLHG 379 (652) Q Consensus 301 ~~~Lw~~SGh~~~y~~~mf~~~~~~~~~~~~~~~~LkPmncp~h~~i~~~~~~SYrdLPlrl~e~~-~~~R~E~sg~l~G 379 (652) T Consensus 241 ~~~l~~~sGH~~~Y~e~Mf~~~~~-----~~~~~~LkPMnCpgH~~i~k~~~~SYR~LP~R~aE~g~~~hR~E~sG~L~G 315 (595) T TIGR00418 241 DSELWEISGHWDHYKERMFPFTEE-----DNQEFMLKPMNCPGHILIFKSSLRSYRDLPLRIAELGTTVHRYEKSGALHG 315 (595) T ss_pred CCCCHHHHHHHHHCCCCCCCCEEE-----CCCCCCCCCCCCHHHHHHHCCCCCCHHHCCCHHHHCCCEEEEEECCCCCCH T ss_conf 565424530545034235401010-----353033456775445330017777732335034331860478842542101 Q ss_pred EEECCCCCCCCCEEECC-HHHHHHHHHHHHHHHHHHHHHHCCCCCEECCCCC-CC-C--CCCCHHHHHHHHHHHHHHHHH Q ss_conf 01056353344210105-3767887899999988766552133210001465-31-1--258603577899999999985 Q gi|254781004|r 380 LMRVRGFTQDDAHVFCT-KEQMFNECLKIHNLIISIYKDFGFEKIMVKLSTR-PE-K--RVGSDALWDDAENIMKGVLDT 454 (652) Q Consensus 380 L~R~ReF~~~Dah~F~~-~eq~~~e~~~~~~~~~~v~~~~g~~~~~~~ls~~-~~-~--~~g~~~~~~~ae~~l~~~l~~ 454 (652) T Consensus 316 L~RvR~FT~dDaHifc~d~dQi~~E~~~~~~l~~~v~~~fgf~~~~~~LS~R~Pe~~~Ky~g~d~~W~~~~~~l~~~l~~ 395 (595) T TIGR00418 316 LKRVRGFTQDDAHIFCTDEDQIKSEIKNQFRLIQKVYSKFGFSNYKYELSTRDPENDKKYIGEDELWEKAESALEEALKE 395 (595) T ss_pred HHHHHHCCCCCCCEEECCHHHHHHHHHHHHHHHHHHHHHHCCCCCEEEEEECCCCCCCCCCCCHHHHHHHHHHHHHHHHC T ss_conf 01644306998524537867799999999999999988728842168998717775455458878999999999999850 Q ss_pred HCCCCCCCCCCCCCCCCCCCCCCCCCCCHHHHCCCCCCCCCCCHHHHCCCCCCCEEEEEC--CCEEEEEEEEECCCHHHH Q ss_conf 021212566752055555545543211002110331001211011102234674167317--972137996403410378 Q gi|254781004|r 455 IKNSSQDRINTGVLLGEGAFYGPKFEYILKDAIGRDWQCGTIQVDFNLPSRFNAFYVNSH--SEKCHPVMIHRAVFGSIE 532 (652) Q Consensus 455 ~~~~~~~~~~~~~~~g~~afygpkid~~~~d~~gr~~~~~tiq~df~~p~~f~l~y~~~d--g~~~~pvmihr~~~Gs~e 532 (652) T Consensus 396 ~~------~~yei~~G~~AFYGPKiDf~~~DaL~R~~q~~TvQlDf~lPeRF~l~Y~~~dqd~~~~~Pv~IHra~~GS~E 469 (595) T TIGR00418 396 LG------VDYEIDEGEGAFYGPKIDFQIKDALGREWQCATVQLDFELPERFDLTYINEDQDNKEKRPVMIHRAILGSIE 469 (595) T ss_pred CC------CCEEEECCCCEEECCEEEEEEEECCCCHHHCCCEEEECCCCCCCCCEEEEECCCCCCCCCEEEECCCCHHHH T ss_conf 79------840550788113022268887510176425881488715887203148420367870067789804400589 Q ss_pred HHHHHHHHHHCCCC-------CCCCCCEEEEEEECC-HHHHHHHHHHHHHHHHCCCEEEEECCCCCCCHHHHHHHHCCCC Q ss_conf 99999999738708-------873378089998579-6689999999999998798899975896636766655434898 Q gi|254781004|r 533 RFIGIMIENFKGNL-------PLWLSPIQAIVTTIT-SSAVEYAQEIANLLKSHHLSIETDFRNETINYKIREHSIKKIP 604 (652) Q Consensus 533 R~ia~liE~~~g~~-------P~wLAP~QV~Iipi~-e~~~eya~~i~~~L~~~girV~~Ddr~~~~G~Kir~a~l~giP 604 (652) T Consensus 470 Rfi~iL~E~~~G~fde~~PMLP~WLaP~QV~viPV~i~~h~~yA~kv~~~L~~~giRv~~D~r~e~lgkKIR~a~~~kiP 549 (595) T TIGR00418 470 RFIAILLEKYAGAFDERLPMLPLWLAPVQVVVIPVSIEKHLDYAKKVAEKLKKEGIRVDVDDRNERLGKKIREAQKQKIP 549 (595) T ss_pred HHHHHHHHHHHHHHHCCCCCCCEECCCEEEEEEECCHHHHHHHHHHHHHHHHHCCCEEEECCCCCCHHHHHHHHHCCCCC T ss_conf 99999998752221146898854217623899705778899999999999985797798838888013320220132206 Q ss_pred EEEEECHHHHHC--CCEEEEECC---CCCEEEECHHHHHHHHHHHC Q ss_conf 899987425325--818999889---88663342999999998731 Q gi|254781004|r 605 IIIICGDKEASE--RSIGIRRFG---STTTQKVSLLDAIPILTKES 645 (652) Q Consensus 605 ~~ivIG~ke~e~--~~Vtir~R~---~~~~~~i~lee~i~~l~~e~ 645 (652) T Consensus 550 y~~V~Gd~E~e~~K~~v~vR~~~t~k~~~~~~m~~~E~~~~~~~~~ 595 (595) T TIGR00418 550 YMLVVGDKEMEELKEAVNVRTRKTLKGQKLEKMSLDEFLEKVRKEV 595 (595) T ss_pred EEEEECCHHHHCCCCEEEECCHHHHCCCCEEEECHHHHHHHHHHCC T ss_conf 7999873023138966852240210463101430999999997339

HHsearch alignment for GI: 254781004 and conserved domain: TIGR00418