>TIGR00389 glyS_dimeric glycyl-tRNA synthetase; InterPro: IPR002315 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 . In eubacteria, glycyl-tRNA synthetase (6.1.1.14 from EC) is an alpha2/beta2 tetramer composed of 2 different subunits , , . In some eubacteria, in archaea and eukaryota, glycyl-tRNA synthetase is an alpha2 dimer, this family. It belongs to class IIc and is one of the most complex synthetases. What is most interesting is the lack of similarity between the two types: divergence at the sequence level is so great that it is impossible to infer descent from common genes. The alpha (see IPR002310 from INTERPRO) and beta subunits (see IPR002311 from INTERPRO) also lack significant sequence similarity. However, they are translated from a single mRNA , and a single chain glycyl-tRNA synthetase from Chlamydia trachomatis has been found to have significant similarity with both domains, suggesting divergence from a single polypeptide chain . The sequence and crystal structure of the homodimeric glycyl-tRNA synthetase from Thermus thermophilus, shows that each monomer consists of an active site strongly resembling that of the aspartyl and seryl enzymes, a C-terminal anticodon recognition domain of 100 residues and a third domain unusually inserted between motifs 1 and 2 almost certainly interacting with the acceptor arm of tRNA(Gly). The C-terminal domain has a novel five-stranded parallel-antiparallel beta-sheet structure with three surrounding helices. The active site residues most probably responsible for substrate recognition, in particular in the Gly binding pocket, can be identified by inference from aspartyl-tRNA synthetase due to the conserved nature of the class II active site , .; GO: 0000166 nucleotide binding, 0004820 glycine-tRNA ligase activity, 0005524 ATP binding, 0006412 translation, 0006426 glycyl-tRNA aminoacylation, 0005737 cytoplasm.

Probab=97.78 E-value=1e-04 Score=55.88 Aligned_cols=196 Identities=17% Similarity=0.270 Sum_probs=137.6 Q ss_pred CCCEEECCHHHHHHHHHHHHHHHHHHHHCC-CCEEHHHHHCCHHHHHHHHHCHHHHHHH---------HHHH-------- Q ss_conf 753010564889999999999986223203-2021235620278898655142247677---------6431-------- Q gi|254780680|r 162 ARFSVLTGHLAHLERALGQFMIDLHTSEHG-YTEVSAPLLVRDEAMYGTGQIPKFADDM---------FCTT-------- 223 (430) Q Consensus 162 srF~~Lkg~~A~Le~ALi~y~ld~~~~~~G-y~~v~~P~lv~~~~~~gtG~lp~f~~~~---------y~~~-------- 223 (430) T Consensus 27 aG~~DyGPLG~~Lk~~I~~~wr~~fi~~e~d~~~id~P~i~~~evlKASGHvd~F~D~~v~Ck~C~~~fRADHl~e~~~~ 106 (606) T TIGR00389 27 AGFWDYGPLGAVLKNNIKNAWRKFFIINERDVLEIDSPIITPEEVLKASGHVDNFTDPMVDCKKCKERFRADHLIEEKLG 106 (606) T ss_pred HHHHHCCCCHHHHHHHHHHHHHHHHCCCCCCEEEECCCCCCCHHHHHHCCCCCCCCCCEEECCCCCCEECHHHHHHHHHH T ss_conf 20010157247899999998887511103653464245337257997528645673122673788804010123256651 Q ss_pred ---HC-------------------------------------------------C-----------EECCCCC-CHHHHH Q ss_conf ---00-------------------------------------------------0-----------2313454-114544 Q gi|254780680|r 224 ---DG-------------------------------------------------R-----------WLIPTSE-VSLTNL 239 (430) Q Consensus 224 ---d~-------------------------------------------------l-----------~Li~TaE-vpL~~~ 239 (430) T Consensus 107 ~~~~~dqqiK~V~~~D~K~~E~iL~~iDG~~~~eL~E~m~~~~i~CP~C~g~~nl~~v~~FNLMF~T~IG~~~~~~~~gY 186 (606) T TIGR00389 107 KDVEGDQQIKDVKLDDVKEYEKILAKIDGETGPELKEVMEKYDINCPNCGGENNLTEVRSFNLMFQTEIGVVGDSKRKGY 186 (606) T ss_pred HHCCCCCCCCCCCHHHHHHHHHHHHHCCCCCHHHHHHHHHHCCCCCCCCCCCCCCCCCHHCCCCCEEEECCCCCCCCEEE T ss_conf 00047610012685457779989755078711567877634278898223545613501204541102113347762241 Q ss_pred HHHH-----------CC--CHHHHCCEEEEEECCCCCCCCCCCCCCCCEEEEEEEEEEEEEECCCC-CCHHHHHHHHHHH Q ss_conf 5342-----------05--95550420885322107884335543432122221020021212786-5014578989999 Q gi|254780680|r 240 YSHE-----------II--ESKSLPLRFTTLAPSFRSEAGSAGRDTRGMLRQHQFWKCELVSITRE-EDSFTEHERMLSC 305 (430) Q Consensus 240 ~~~~-----------~l--~~~~LPik~~~~s~cfR~EaGs~GkdtrGl~RvHQF~KVE~~~~~~p-e~S~~~~e~~~~~ 305 (430) T Consensus 187 LRPETAQG~FinFk~LL~~~r~klPFgvAQiGKSfRNEIsPr----~gl~R~REF~QaE~E~FV~P~~k~h~~F~~~~~~ 262 (606) T TIGR00389 187 LRPETAQGIFINFKRLLQFFRNKLPFGVAQIGKSFRNEISPR----QGLIRLREFEQAEIEFFVDPEDKSHPKFEEVKQE 262 (606) T ss_pred CCCHHCCCCCHHHHHHHHHHCCCCCEEEEEECCEEECCCCCC----CCEEEECHHHHHHHHHCCCCCCCCCCCHHHHHHC T ss_conf 476010475121689999745899648997441360400389----8757103154466874259600167200145405 Q ss_pred H---------------------------------------------HHHHHHHC-CH---HHHCCCCCHHCCCHHHEEEE Q ss_conf 9---------------------------------------------99999841-06---75303780117844340241 Q gi|254780680|r 306 A---------------------------------------------EEILKRLD-LH---YRVVSLCTGDLGFSACKTYD 336 (430) Q Consensus 306 ~---------------------------------------------~~i~~~L~-lp---yRvv~~~sgdlg~~a~~~~D 336 (430) T Consensus 263 ~~~Llp~~R~~~E~g~~~~~v~~t~gEAVe~G~i~ne~L~YFia~~~~FL~~igkI~~dklRFrqH~~~E~AHYA~dcwD 342 (606) T TIGR00389 263 VVPLLPAERQMQESGESEKPVKMTIGEAVEKGIIENETLAYFIALVKRFLLEIGKINPDKLRFRQHLKNEMAHYAKDCWD 342 (606) T ss_pred CCCCCCCCCCCHHCCCCCCHHHHHHHHHHHCCCCCCHHHHHHHHHHHHHHHHHCCCCHHHHHHHHCCCHHHHHHHHHHEE T ss_conf 00136764540001576405444178886346521006899999999999865278878852331360045565553623 Q ss_pred EEEECCCCCCEEEEEEECCCCCHHHH Q ss_conf 01101004833237531021007645 Q gi|254780680|r 337 LEVWLAGQNLYREISSCSTCGNFQSR 362 (430) Q Consensus 337 iE~w~P~~~~y~Ev~S~Snc~D~Qsr 362 (430) T Consensus 343 ~E~~t~~y-GwiE~~GiADR~~yDL~ 367 (606) T TIGR00389 343 AEILTSRY-GWIEVVGIADRTDYDLT 367 (606) T ss_pred EEEECCCC-CCEEEEEEECCCCCCHH T ss_conf 55665798-73899874067722168

HHsearch alignment for GI: 254780680 and conserved domain: TIGR00389