>TIGR01161 purK phosphoribosylaminoimidazole carboxylase, ATPase subunit; InterPro: IPR005875 Phosphoribosylaminoimidazole carboxylase is a fusion protein in plants and fungi, but consists of two non-interacting proteins in bacteria, PurK and PurE. This family represents PurK, N5-carboxyaminoimidazole ribonucleotide (N5_CAIR) synthetase, which catalyzes the conversion of 5-aminoimidazole ribonucleotide (AIR), ATP, and bicarbonate to N5-CAIR, ADP, and Pi. PurE converts N5-CAIR to CAIR. In the presence of high concentrations of bicarbonate, PurE is reported able to convert AIR to CAIR directly and without ATP. PurK belongs to the ATP grasp superfamily of C-N ligase enzymes. Each subunit of PurK is composed of three domains (A, B, and C). The B domain contains a flexible, glycine-rich loop (B loop, T123-G130) that is disordered in the sulphate-PurK structure and becomes ordered in the MgADP-PurK structure. MgADP is wedged between the B and C domains, as with all members of the ATP grasp superfamily. Other enzymes in this superfamily contain a conserved Omega loop proposed to interact with the B loop, define the specificity of their nonnucleotide substrate, and protect the acyl phosphate intermediate formed from this substrate. PurK contains a minimal Omega loop without conserved residues. In the reaction catalyzed by PurK, carboxyphosphate is the putative acyl phosphate intermediate. The sulphate of the sulphate ion-liganded PurK interacts electrostatically with Arg 242 and the backbone amide group of Asn 245, components of the J loop of the C domain. This sulphate may reveal the location of the carboxyphosphate binding site. Conserved residues within the C-terminus of the C domain define a pocket that is proposed to bind AIR in collaboration with an N-terminal strand loop helix motif in the A domain (P loop, G8-L1). The P loop is proposed to bind the phosphate of AIR on the basis of similar binding sites observed in PurN and PurE and proposed in PurD and PurT, four other enzymes in the purine pathway .; GO: 0004638 phosphoribosylaminoimidazole carboxylase activity, 0006189 'de novo' IMP biosynthetic process, 0009320 phosphoribosylaminoimidazole carboxylase complex.

Probab=99.51 E-value=3.7e-11 Score=106.12 Aligned_cols=263 Identities=23% Similarity=0.358 Sum_probs=201.6 Q ss_pred EEEEECCCCCCCCCHHHHHHHHHHHHHHHHHCCCEEEEECCCCCEEECCCC--CCC--CEEECCC-CHHHHHHHH----- Q ss_conf 999976775420505466688899999999879789997487650107845--131--0043379-999999999----- Q gi|254780439|r 9 TLLIIGAGPIVIGQACEFDYSGTQACKALKEEGYRIILVNSNPATIMTDPD--LAD--ATYTEPI-TPEVVAKII----- 78 (1162) Q Consensus 9 kvLviGsGpi~IGqa~EfDys~~qa~~alke~Gi~vVlVNsNpaTi~TD~~--~aD--~vY~ePl-t~e~v~~Ii----- 78 (1162) T Consensus 1 ~vGilGGGQL-----------G~M~~~aA~~LG~~~~VL~~~~~----~PA~q~Ad~~~~v~a~~~d~~~i~~La~~cDv 65 (386) T TIGR01161 1 TVGILGGGQL-----------GRMLALAAKKLGIKVAVLDPDAN----SPAKQVADSREHVLASFTDPEAIRELAEACDV 65 (386) T ss_pred CEEEEECCHH-----------HHHHHHHHHHCCCEEEEECCCCC----CCCCCCCCCCCEEEEEECCHHHHHHHHHHCCE T ss_conf 9689718848-----------99999987127958998548989----73111289855799851487899999976565 Q ss_pred ---HHHCCCEEEECCCCCHHHHHHHHHHHCCCHHHHCCEEECCCHHHHHHHCCHHHHHHHHHHCCCCCCCCCCCCCCCCC Q ss_conf ---86289889975887026888899887596288287571499899986058899999999878988862000234433 Q gi|254780439|r 79 ---EKERPDAILPTTGGQTALNTALSLKRMGVLDRYGVEMIGAKPETIDKAEDRSLFSKAMQNIPLATPKSILANATDIK 155 (1162) Q Consensus 79 ---~~E~pDaIlp~~GGqtalnl~~~L~e~gil~~~~v~~lG~~~~~I~~~edR~~F~~~l~~~gip~~~s~~~~~~~~~ 155 (1162) T Consensus 66 iT~E~Ehv~~~--~L~---------~L~~~g~----~~~-~~P~~~~l~~~~dk~~qK~~L~~~g~~vp~f~~~~~---- 125 (386) T TIGR01161 66 ITFEFEHVDVE--ALE---------KLEARGD----KVK-VRPSPEALAIIQDKLTQKQFLQKLGLPVPPFVVIEI---- 125 (386) T ss_pred EEEEECCCCCH--HHH---------HHHHCCC----EEE-EECCHHHHHHHHCHHHHHHHHHHCCCCCCCCCEEEC---- T ss_conf 54310137856--789---------9983598----477-603889999883658999999966899884120223---- Q ss_pred CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCHHHHHHHHHHCCCCEEEEECCCC-CCCCCCC Q ss_conf 333233333334444444433332221111112334444444554448999999999871996999413267-8664511 Q gi|254780439|r 156 EHDRKLHEEERENLKKTLSKEELDAALYALELKWNLEENDRKHRYICHAMAVAVQALDEIGLPLIIRPSFTL-GGTGGGI 234 (1162) Q Consensus 156 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~s~~ea~~~a~~iGyPvivRps~~l-GG~G~~i 234 (1162) T Consensus 126 -----------------------------------------------~~~~~~~~~~~~~g~p~VlK~~~gGYDGrGq~~ 158 (386) T TIGR01161 126 -----------------------------------------------KDEEELDSALQELGFPVVLKARRGGYDGRGQFV 158 (386) T ss_pred -----------------------------------------------CCHHHHHHHHHHCCCCEEEEEEECCCCCCCCEE T ss_conf -----------------------------------------------684257899987398479984206527731089 Q ss_pred CCCHHHHHHHHHHHHHHCCCC--CEEEEEECCCCEEEEEEEEEECCCCEEEEEECCCCCCC--CCCCCEEEEECCCCCCC Q ss_conf 169999999999899857998--27986644997899999997289988999630000001--00001013433732289 Q gi|254780439|r 235 AYNRSEFLEIVENGLHASPTT--EVLIEESVLGWKEYELEMMRDIKGNCIVVCSIENLDPM--GVHTGDSITVAPALTLT 310 (1162) Q Consensus 235 v~n~eeL~~~~~~al~~s~~~--~vlIeksl~g~kEiE~eVirD~~gn~i~v~~~En~dp~--GiHtGDSi~vaP~qTL~ 310 (1162) T Consensus 159 i~~~~~~~~----~~~~~~~~~~~~~~E~fV~F~~Elsv~vaR~~~G~~~~YP~ven~~~ddagIl---~~~~aPAPa~p 231 (386) T TIGR01161 159 IKSEADLPQ----ALKELGDKEEELIVEEFVPFERELSVIVARSADGEIAFYPVVENIHQDDAGIL---RLVVAPAPAVP 231 (386) T ss_pred ECCHHHHHH----HHHHCCCCCEEEEEEECCCCCEEEEEEEEECCCCCEEECCCEEEEEECCCCEE---EEEEECCCCCC T ss_conf 747432889----99852888405898523562006999999778974888286123565277877---89863377783 Q ss_pred HHH---HHHHHHHHHHHHHHHCCCCCCCEEEEEEEC-CCC----EEEEEEECCCCCHHH Q ss_conf 889---999999999999871834576468999955-898----499985044431035 Q gi|254780439|r 311 DKE---YQLMRNAAIAVLKEIGVESGGANVQFAVNP-KNG----KMVVIEMNPRVSRSS 361 (1162) Q Consensus 311 d~~---~q~LR~~a~kI~r~lgi~vG~~nVQFAv~p-~~~----~~yvIEvNpR~sRss 361 (1162) T Consensus 232 ~~~~Q~~~~A~~~A~~~~~~L~~-VG~~avE~F~~Pa~dGP~P~~LLvNElAPR~HNSG 289 (386) T TIGR01161 232 DALVQQQKKAQELARRLAEELDY-VGVLAVEMFLLPAKDGPEPDELLVNELAPRPHNSG 289 (386) T ss_pred HHHHHHHHHHHHHHHHHHHHCCC-EEEEEEEEEEECCCCCCCCCCEEEEEECCCCCCCH T ss_conf 45789999999999999986196-17888999830688789512056610257889841

HHsearch alignment for GI: 254780439 and conserved domain: TIGR01161