>TIGR00440 glnS glutaminyl-tRNA synthetase; InterPro: IPR004514 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 . Glutaminyl-tRNA synthetase (6.1.1.18 from EC) is a class Ic synthetase and shows several similarities with glutamyl-tRNA synthetase concerning structure and catalytic properties. It is an alpha2 dimer. Glutaminyl-tRNA synthetase is a relatively rare synthetase, found in the cytosolic compartment of eukaryotes, in Escherichia coli and a number of other Gram-negative bacteria, and in Deinococcus radiodurans. In contrast, the pathway to Gln-tRNA in mitochondria, Archaea, Gram-positive bacteria, and a number of other lineages is by misacylation with Glu followed by transamidation to correct the aminoacylation to Gln.; GO: 0000166 nucleotide binding, 0004819 glutamine-tRNA ligase activity, 0005524 ATP binding, 0006412 translation, 0006425 glutaminyl-tRNA aminoacylation, 0005737 cytoplasm.

Probab=96.47  E-value=0.0033  Score=39.90  Aligned_cols=106  Identities=18%  Similarity=0.336  Sum_probs=64.3

Q ss_pred             CCCCCCCCCCCCHHHHHHHHHHHHHHHHHCCCCCCCCCCCCCCCHHHHHHHHHHCCCHHHHHHHHHHHHHHHHHHCCCEE
Q ss_conf             77897898740047797789999997771898556768814020589999998099999999999999999999819176
Q gi|254780802|r   41 MFPYPSGNIHMGHLRNYVIGDVVARFMRASGYSVLHPMGWDAFGMPAENAAREHNVHPKMWTYQNIKVMRKQLQSIGLSI  120 (869)
Q Consensus        41 ~pPy~nG~lHiGH~~~~t~~Dv~aRy~rm~G~~Vl~~~G~d~~GlPie~~~~e~~~~~~~~~~~~i~~~k~~~~~lG~~~  120 (869)
T Consensus         5 FPPEPNGYLHIGHaK~I~~NFG~Ak~y--~G~C~L---RFDD-------------TNP~KE~~EY~eSIK~~V~WLGFkw   66 (564)
T TIGR00440         5 FPPEPNGYLHIGHAKSICLNFGLAKEY--KGTCNL---RFDD-------------TNPVKEDVEYVESIKRDVEWLGFKW   66 (564)
T ss_pred             CCCCCCCCEEHHHHHHHHHHCCCCCCC--CCCEEE---ECCC-------------CCCCCCCCHHHHHHHHHHHHCCCCC
T ss_conf             885578730010243134420320201--763644---2167-------------8886466017888752222225124


Q ss_pred             ECCCCEECCCHHHHHHHHHHHHHHHHCCCEEECCEEEECCCCCCCCCCHHHHHCCCCCC
Q ss_conf             64698214773599999999999998896341221332147767677898984385334
Q gi|254780802|r  121 DWSKDFATCDVDYYHCQQLLFLDFMKHNVIVRKTAQVNWDPVEQTVLANEQVINGRGWR  179 (869)
Q Consensus       121 DW~r~y~T~d~~y~~~v~w~f~~L~~kGliyrg~~pV~wcp~~~t~la~~Ev~~g~~~~  179 (869)
T Consensus        67 ~g~~~YsS---DYFD~Ly~~A~~LI~~G~AY-----V~~~-------t~e~i~~~RG~~  110 (564)
T TIGR00440        67 EGKIRYSS---DYFDELYRYAVELIKKGLAY-----VDEL-------TPEEIREYRGTL  110 (564)
T ss_pred             CCCEEECH---HHHHHHHHHHHHHHHCCCEE-----EECC-------CHHHHHHCCCCC
T ss_conf             77313330---46889999999998679606-----7537-------878986327602