>cd02163 PPAT_a Phosphopantetheine adenylyltransferase (PPAT) is an essential enzyme in bacteria that catalyses a rate-limiting step in coenzyme A (CoA) biosynthesis, by transferring an adenylyl group from ATP to 4'-phosphopantetheine, yielding dephospho-CoA (dPCoA). Each phosphopantetheine adenylyltransferase (PPAT) subunit displays a dinucleotide-binding fold that is structurally similar to that in class I aminoacyl-tRNA synthetases. Superposition of bound adenylyl moieties from dPCoA in PPAT and ATP in aminoacyl-tRNA synthetases suggests nucleophilic attack by the 4'-phosphopantetheine on the -phosphate of ATP. The proposed catalytic mechanism implicates transition state stabilization by PPAT without involving functional groups of the enzyme in a chemical sense in the reaction. The homologous active site attachment of ATP and the structural distribution of predicted sequence-binding motifs in PPAT classify the enzyme as belonging to the nucleotidyltransferase superfamily.

Probab=98.49 E-value=4.1e-07 Score=67.10 Aligned_cols=130 Identities=18% Similarity=0.275 Sum_probs=78.1 Q ss_pred EEEECCCCCCHHHHHHHHHHHHHHCCCCEEEEEECCCHHHHHCCCCCCCCCCHHHHHHHHHHHC--CCCCCCCCCCHHHH Q ss_conf 9993156502899999999999502797799983798689847888662000078999988511--31000225640577 Q gi|254780846|r 22 VAIGNFDGIHLGHHLILEQAIKIANNSPITVLSFNPHPRTIIQSSSPIFTLSPPSIQEKILEKM--GFSALIRYKFTLET 99 (324) Q Consensus 22 vtiG~FDGvH~GHq~Li~~~~~~a~~~~~~viTF~p~P~~~~~~~~~~~~l~~~~~k~~~l~~~--Gid~vi~~~F~~~~ 99 (324) T Consensus 2 ifpGSFDP~t~GHldii~ra~~lFD~vi-i~i~~--------N~~K~--~~f~~~eR~~~i~~~~~~~~nV~V~~~~--- 67 (152) T cd02163 2 VYPGSFDPITNGHLDIIERASRLFDEVI-VAVAV--------NPSKK--PLFSLEERVELIREATKHLPNVEVVGFD--- 67 (152) T ss_pred CCCCCCCCCCCCHHHHHHHHHHHCCEEE-EEEEC--------CCCCC--CCCCHHHHHHHHHHHHCCCCCEEEEEEC--- T ss_conf 0786779884009999999998789899-99622--------88767--6689999999999974589987999967--- Q ss_pred HHCCCHHHHHHHHCCCCCEEEEEEC----CCCCCCCCCCCCHHHHHH-HHHCCCCEEEECCHHHCCCCCCCCHHHHHHHH Q ss_conf 5228302688862142780299983----455303377556024677-51012641676152230233302303689998 Q gi|254780846|r 100 ANYSAEQFIQKVLVEWLEVKTVITG----TKFRFGKDRAGDRGILQK-RGEKYGFHTVFIDELRNNKSQIVSSSNIRTAL 174 (324) Q Consensus 100 a~ls~e~Fi~~iL~~~l~~k~ivVG----~Df~FG~~r~Gd~~~L~~-~~~~~g~~v~~i~~~~~~~~~~ISSt~IR~~l 174 (324) T Consensus 68 ------gl~vd~-ak~~~a~~ivRGlR~~~DfeyE~----~~a~~Nr~L~--~~IeTvfl~~--~~~~~~ISSs~VRel~ 132 (152) T cd02163 68 ------GLLVDF-ARKVGANVIVRGLRAVSDFEYEF----QMAGMNRKLA--PEIETVFLMA--SPEYSFISSSLVKEVA 132 (152) T ss_pred ------CHHHHH-HHHCCCEEEEECCCCHHHHHHHH----HHHHHHHHHC--CCCCEEEEEC--CCCCCEEEHHHHHHHH T ss_conf ------669999-99769829996586404889999----9999999608--9986899847--9666576189999999 Q ss_pred H-HHHHH Q ss_conf 7-25899 Q gi|254780846|r 175 T-KGHVL 180 (324) Q Consensus 175 ~-~Gdi~ 180 (324) T Consensus 133 ~~ggdi~ 139 (152) T cd02163 133 SLGGDVS 139 (152) T ss_pred HCCCCHH T ss_conf 8399944

HHsearch alignment for GI: 254780846 and conserved domain: cd02163