>TIGR00435 cysS cysteinyl-tRNA synthetase; InterPro: IPR002308 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 . Cysteinyl-tRNA synthetase (6.1.1.16 from EC) is an alpha monomer and belongs to class Ia.; GO: 0000166 nucleotide binding, 0004817 cysteine-tRNA ligase activity, 0005524 ATP binding, 0006412 translation, 0006423 cysteinyl-tRNA aminoacylation, 0005737 cytoplasm.

Probab=97.77  E-value=8e-05  Score=51.50  Aligned_cols=38  Identities=29%  Similarity=0.447  Sum_probs=35.4

Q ss_pred             CCCCCCCCHHHHHHHHHHHHHHHHHH-CCCCCCCCCCCC
Q ss_conf             25588976215778566878998767-089826788882
Q gi|254780445|r   63 PYANGHIHIGHALNKILKDVIVRSFQ-MRNFNACFVPGW  100 (963)
Q Consensus        63 Py~nG~lH~GH~~n~~~kDi~~Ry~r-m~G~~Vl~~~Gw  100 (963)
T Consensus        30 pTVYd~~HiGhaR~~i~fD~~~R~L~d~~GY~V~yV~Ni   68 (660)
T TIGR00435        30 PTVYDYAHIGHARTAIVFDVLRRYLEDYLGYEVQYVQNI   68 (660)
T ss_pred             CHHHHHHCCCCCCCHHHHHHHHHHHHHHHCCEEEEEEEE
T ss_conf             317621030346630257888999988758867888643