>TIGR00471 pheT_arch phenylalanyl-tRNA synthetase, beta subunit; InterPro: IPR004531 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 . Phenylalanyl-tRNA synthetase (6.1.1.20 from EC) is an alpha2/beta2 tetramer composed of 2 subunits that belongs to class IIc. In eubacteria, a small subunit (pheS gene) can be designated as beta (E. coli) or alpha subunit (see IPR002319 from INTERPRO). Reciprocally the large subunit (pheT gene) can be designated as alpha (E. coli) or beta. In all other kingdoms the two subunits have equivalent length in eukaryota, and can be identified by specific signatures. The enzyme from Thermus thermophilus has an alpha 2 beta 2 type quaternary structure and is one of the most complicated members of the synthetase family. Identification of phenylalanyl-tRNA synthetase as a member of class II aaRSs was based only on sequence alignment of the small alpha-subunit with other synthetases . This family describes the beta subunit. The beta subunits break into two subfamilies that are considerably different in sequence, length, and pattern of gaps (see also IPR004532 from INTERPRO). This family represents the subfamily that includes the beta subunit from eukaryotic cytosol, the archaea, and spirochetes.; GO: 0000166 nucleotide binding, 0004826 phenylalanine-tRNA ligase activity, 0005524 ATP binding, 0006412 translation, 0006432 phenylalanyl-tRNA aminoacylation, 0005737 cytoplasm.

Probab=96.98  E-value=0.0011  Score=42.79  Aligned_cols=109  Identities=24%  Similarity=0.283  Sum_probs=77.2

Q ss_pred             ECCCCCHHCCCCHHHH---HHHHHHHHHHHHHHCCCEEEECCCCCCHHHHHHCCCCHHHHHHHCCHHHCCCCCC-----E
Q ss_conf             0038811104316999---9999999999998669889735751246898771973112222104021378620-----0
Q gi|254780870|r   34 QHSKGIYSWLPLGQKA---LDNVNAIIREEQNRTGAIEMSVPTLQSADLWVESGRYDSYGKEMLRLADRNDKAM-----I  105 (449)
Q Consensus        34 ~~~~G~~~~lP~G~~i---~~~le~~~r~~~~~~G~~ei~tP~l~~~eL~~~SGh~d~~~~em~~~~d~~~~~~-----~  105 (449)
T Consensus       375 ~~~pE~P~~~t~g~~~Plp~~~~~~~~R~~mvG~GF~EVi~l~L~s~~-------------~~~~~mR~~d~~~k~~v~V  441 (605)
T TIGR00471       375 NIEPELPKILTIGRLKPLPLEKVSDIIREIMVGLGFQEVISLTLTSEE-------------VLFKRMRIEDNNFKLAVKV  441 (605)
T ss_pred             CCCCCCCCHHHHHCCCCCCHHHHHHHHHHHHHCCCHHHHHHCCCCCHH-------------HHHHHHCCCCCCCHHHHHH
T ss_conf             068777712222104888777887576542204704342410047806-------------9999807578872003331


Q ss_pred             ECCCCCCCCCCCHHHCC----------CCCCCCCEEEEECCC-CCCCCCCCCCCCCCCEEEEEE
Q ss_conf             03455543101100001----------342013402641465-334566767543453166874
Q gi|254780870|r  106 YGPTHEEVMTDIFRSHI----------KSYRNLPFTFYQIQL-KFRDELRPRFGVMRSREFLMK  158 (449)
Q Consensus       106 LrP~~~e~~~~i~~~~~----------~SYr~LPlr~y~ig~-~fR~E~rp~~GL~R~ReF~q~  158 (449)
T Consensus       442 ~~P~t~e~~--~~R~SlLP~LLe~~~~Nk~~~lP~KiFE~GDVV~~d~~~erk-~~~~r~~~~l  502 (605)
T TIGR00471       442 ANPLTLEYT--IVRTSLLPGLLETLSENKHHELPQKIFEIGDVVVKDDDSERK-ETRSRVVTKL  502 (605)
T ss_pred             CCCCCCCHH--HHHHHHHHHHHHHHHHHCCCCCCCEEEEEEEEEEECCCHHHH-HHCCEEEEEE
T ss_conf             178762333--776562236788886514899882078874388828720122-3056255567