>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=99.28 E-value=7.6e-09 Score=87.85 Aligned_cols=288 Identities=20% Similarity=0.328 Sum_probs=219.4 Q ss_pred EEEECCCCEEECCCCCCCHHHHHHHHHHHHCCCCEEEEECCCCCCCCCCCCCC------EEEEEECCHHHHHHHHHHHCC Q ss_conf 89972763020147665318999999999659806996068652112324586------379841678899999987485 Q gi|254780439|r 621 IVILGGGPNRIGQGIEFDYCCCHASFSLKEAGFETIMINCNPETVSTDYDIAD------RLYFESLTEEDILEILRVEQQ 694 (1162) Q Consensus 621 viVlGsGp~RIGqgiEFDy~~v~a~~aLr~~G~~tImIN~NPETVSTDyd~sD------rLYFEplt~E~V~~I~~~E~p 694 (1162) T Consensus 2 vGilGGGQL--------G~M~~~---aA~~LG~~~~VL~~~~~--~PA~q~Ad~~~~v~a~~~d~~~i~~La~~cD---- 64 (386) T TIGR01161 2 VGILGGGQL--------GRMLAL---AAKKLGIKVAVLDPDAN--SPAKQVADSREHVLASFTDPEAIRELAEACD---- 64 (386) T ss_pred EEEEECCHH--------HHHHHH---HHHHCCCEEEEECCCCC--CCCCCCCCCCCEEEEEECCHHHHHHHHHHCC---- T ss_conf 689718848--------999999---87127958998548989--7311128985579985148789999997656---- Q ss_pred CCCCCEEEEECCCHHHHHHHHHHHHCC--CEEEECCCCHHHHCCCHHHHHHHHHHCCCCCCCCCCCC--CHHHHHHHHHH Q ss_conf 678227998445124668988888759--83861275203310286789998887098668542112--15665556553 Q gi|254780439|r 695 KGELVGIIVQFGGQTPLKLSKILEKNQ--IPILGTQPDSIDLAEDRDRFQKLLMELDLNQPRNGISH--SVEHARLIACE 770 (1162) Q Consensus 695 ~g~~~~vi~q~gGqt~~~la~~L~~~g--v~ilGts~~~Id~aEDR~~F~~ll~~l~i~~p~~~~a~--s~eea~~~a~~ 770 (1162) T Consensus 65 ------viT~E~Ehv~~~~L~~L~~~g~~~~~~-P~~~~l~~~~dk~~qK~~L~~~g~~vp~f~~~~~~~~~~~~~~~~~ 137 (386) T TIGR01161 65 ------VITFEFEHVDVEALEKLEARGDKVKVR-PSPEALAIIQDKLTQKQFLQKLGLPVPPFVVIEIKDEEELDSALQE 137 (386) T ss_pred ------EEEEEECCCCCHHHHHHHHCCCEEEEE-CCHHHHHHHHCHHHHHHHHHHCCCCCCCCCEEECCCHHHHHHHHHH T ss_conf ------554310137856789998359847760-3889999883658999999966899884120223684257899987 Q ss_pred CCCCEEEECCCCC-CCCCCEEECCHHHHHHHHHHHHHHCCCCCCCCCCCCCCCCCCCCCCCCC--CEEEEEECCCCEEEE Q ss_conf 6971675134444-5654125548999999999752101322111122333333334557777--456702201201001 Q gi|254780439|r 771 IGFPLLIRPSYVL-GGRAMQIVYSENMLQDYLLDTLPGLVSEEIKRQYPNDKTGQINTLLGTH--PLLFDSYLSDAMEID 847 (1162) Q Consensus 771 iGyPVLVRPSyVL-GG~~M~Iv~~~~eL~~yl~~a~~~~~~~~~~~~~~~~~~~~~~~vs~~~--pVlIdkfl~~a~EiE 847 (1162) T Consensus 138 ~g~p~VlK~~~gGYDGrGq~~i~~~~~~~~~~~~-------------------------~~~~~~~~~~E~fV~F~~Els 192 (386) T TIGR01161 138 LGFPVVLKARRGGYDGRGQFVIKSEADLPQALKE-------------------------LGDKEEELIVEEFVPFERELS 192 (386) T ss_pred CCCCEEEEEEECCCCCCCCEEECCHHHHHHHHHH-------------------------CCCCCEEEEEEECCCCCEEEE T ss_conf 3984799842065277310897474328899985-------------------------288840589852356200699 Q ss_pred EEEEEEC-CCEEEEEEEC--CCCHHCCCCCCEEEEECCCCCCHHH---HHHHHHHHHHHHHHCCCCCCCEEEE-EE--CC Q ss_conf 0102307-9849998520--1102152457627981686689999---9999999999987413357624788-51--28 Q gi|254780439|r 848 VDALCQN-DQVIVVGIIE--HIEEAGIHSGDSACSLPSRSLSQQL---KDELISQTKALAGALNVIGLINVQY-AI--KD 918 (1162) Q Consensus 848 VDai~Dg-~~v~I~gimE--HiE~aGVHSGDS~~v~PpqsLs~~~---~~~i~~~t~~ia~~L~v~G~~NIQf-a~--kd 918 (1162) T Consensus 193 v~vaR~~~G~~~~YP~ven~~~ddagIl---~~~~aPAPa~p~~~~Q~~~~A~~~A~~~~~~L~~VG~~avE~F~~Pa~d 269 (386) T TIGR01161 193 VIVARSADGEIAFYPVVENIHQDDAGIL---RLVVAPAPAVPDALVQQQKKAQELARRLAEELDYVGVLAVEMFLLPAKD 269 (386) T ss_pred EEEEECCCCCEEECCCEEEEEECCCCEE---EEEEECCCCCCHHHHHHHHHHHHHHHHHHHHCCCEEEEEEEEEEECCCC T ss_conf 9999778974888286123565277877---8986337778345789999999999999986196178889998306887 Q ss_pred C----EEEEEEECCCCCCCHHHHHHHHCCCHHHHHHHHHCCCCCCC Q ss_conf 8----59998524444563045677739889999999985972100 Q gi|254780439|r 919 G----KIYILEVNPRASRTVPFIAKAIGFPVAKVAARIIAGESLDA 960 (1162) Q Consensus 919 ~----~iYVIEvNpRaSRtvPfvSKatG~pl~~iAt~v~lG~~L~~ 960 (1162) T Consensus 270 GP~P~~LLvNElAPR~HNSGHyTlDgc~tSQFE~hLRAi~~LPLg~ 315 (386) T TIGR01161 270 GPEPDELLVNELAPRPHNSGHYTLDGCSTSQFEQHLRAILGLPLGS 315 (386) T ss_pred CCCCCCEEEEEECCCCCCCHHHHHHHHHHHHHHHHHHHHCCCCCCC T ss_conf 8951205661025788984126566543317999999970889874

HHsearch alignment for GI: 254780439 and conserved domain: TIGR01161