>TIGR00398 metG methionyl-tRNA synthetase; InterPro: IPR002304 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 . Methionyl-tRNA synthetase (6.1.1.10 from EC) is an alpha 2 dimer that belongs to class Ia. In some species (archaea, eubacteria and eukaryota) a coding sequence, similar to the C-term end of MetRS, is present as an independent gene which is a tRNA binding domain as a dimer. In eubacteria, MetRS can also be splitted in two sub-classes corresponding to the presence of one or two CXXC domain specific to zinc binding. The crystal structures of a number of methionyl-tRNA synthases are known , , .; GO: 0000166 nucleotide binding, 0004825 methionine-tRNA ligase activity, 0005524 ATP binding, 0006412 translation, 0006431 methionyl-tRNA aminoacylation, 0005737 cytoplasm.

Probab=96.42  E-value=0.027  Score=35.48  Aligned_cols=64  Identities=16%  Similarity=0.153  Sum_probs=43.4

Q ss_pred             CCCCCCHHHHHH-HHH--HHHHHHHHCCCCEEEEEE-EHHH-------HCCCCC-HHHHHHHH-HHHHHHHHHCCCC
Q ss_conf             896781055798-899--999998505995899973-1157-------307898-58999999-9999999962868
Q gi|254780794|r   14 PTGVLHLGNYLG-MIR--NVIRRQETCNHLGMYFIA-DLHA-------ITNNIV-QENLRYQS-RLFVASFLAAGVD   77 (355)
Q Consensus        14 PtG~~HLG~y~g-~i~--~~i~lq~~~~~~~~~~IA-D~ha-------lt~~~~-~~~~~~~~-~~~~~~~lA~Gld   77 (355)
T Consensus        10 ~Ng~pHlGH~~st~~~AD~~~RY~~~~G~~v~f~cGTDEHG~kI~~~A~~~g~tqP~~~vd~~~~~f~~~~~~lnI~   86 (573)
T TIGR00398        10 ANGKPHLGHAYSTTILADVYARYKRLRGYEVLFVCGTDEHGTKIELKAEQEGLTQPKELVDKYHEEFKKLWKWLNIS   86 (573)
T ss_pred             CCCCHHHHHHHHHHHHHHHHHHHHHCCCCEEEEEECCCCCCCHHHHHHHHCCCCCHHHHHHHHHHHHHHHHHHHCCC
T ss_conf             78711210366777899999999852897478985134468788886987089964899999999999999872845