>TIGR00396 leuS_bact leucyl-tRNA synthetase; InterPro: IPR002302 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 . Leucyl tRNA synthetase (6.1.1.4 from EC) is an alpha monomer that belongs to class Ia. There are two different families of leucyl-tRNA synthetases. This family includes the eubacterial and mitochondrial synthetases. The crystal structure of leucyl-tRNA synthetase from the hyperthermophile Thermus thermophilus has an overall architecture that is similar to that of isoleucyl-tRNA synthetase, except that the putative editing domain is inserted at a different position in the primary structure. This feature is unique to prokaryote-like leucyl-tRNA synthetases, as is the presence of a novel additional flexibly inserted domain . ; GO: 0000166 nucleotide binding, 0004823 leucine-tRNA ligase activity, 0005524 ATP binding, 0006412 translation, 0006429 leucyl-tRNA aminoacylation, 0005737 cytoplasm.

Probab=98.01  E-value=1.5e-06  Score=66.22  Aligned_cols=53  Identities=23%  Similarity=0.409  Sum_probs=47.1

Q ss_pred             CCC--CCCCCCCCEEEEEEHHHEECCCCCHHHHHHHHHCCCCC--EECCCCCHHHHHHHH
Q ss_conf             222--35666553244431222121454202333432002441--121443113567641
Q gi|254780933|r  381 IVP--HCERSGVTIEPCITEQWYLDAKVLAESAIRSAKNGCLS--FIPQSWDKSYYEWLE  436 (947)
Q Consensus       381 ~~p--~c~R~~~~i~~~~~~QWfi~~~~~~~~~l~~~~~~~i~--~~P~~~~~~~~~wl~  436 (947)
T Consensus       174 S~Gna~SwR~~~~Vekk~l~QW~LKIT~YAe~LL~dLe--~L~D~W-P~~VK~MQrNWIG  230 (916)
T TIGR00396       174 SDGNARSWRGGTPVEKKELKQWFLKITAYAEELLNDLE--ELDDHW-PESVKEMQRNWIG  230 (916)
T ss_pred             CCCCCEEECCCCCEEEEECCCCEEHHHHHHHHHHHHHH--CCCCCC-CHHHHHCCCCCCC
T ss_conf             78985322487844663067510113378898541142--046788-7313640454565