>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=98.66 E-value=4e-07 Score=67.09 Aligned_cols=215 Identities=21% Similarity=0.352 Sum_probs=137.2 Q ss_pred HHHHHHHHHCCCEEEEEEHHHEEE----EC--CEEEEEEEEEEEECCCCCEEEECCCCCCCHH-HCCEEEEECCCCCCHH Q ss_conf 999999998898899995412489----99--8999999999980777412650464435210-0636688328862247 Q gi|254780696|r 25 FAIALEAQVRGYQIFHYTPDQLYM----RD--SKIYANTQPLSLDEKKEQYYSLGEEKIIDLS-QMDVILIRQDPPFNMH 97 (316) Q Consensus 25 ~~Lm~eAq~RGheV~~~~~~dL~~----~~--g~v~A~~~~i~i~~~~~~~f~~~~~~~~~L~-~fD~i~iR~dPp~d~~ 97 (316) T Consensus 12 ~M~~~aA~~LG~~~~VL~~~~~~PA~q~Ad~~~~v~a~~~d------~~--------~i~~La~~cDviT------~E~E 71 (386) T TIGR01161 12 RMLALAAKKLGIKVAVLDPDANSPAKQVADSREHVLASFTD------PE--------AIRELAEACDVIT------FEFE 71 (386) T ss_pred HHHHHHHHHCCCEEEEECCCCCCCCCCCCCCCCEEEEEECC------HH--------HHHHHHHHCCEEE------EEEC T ss_conf 99999871279589985489897311128985579985148------78--------9999997656554------3101 Q ss_pred HHHHHHHHHHHCC-C--CEEECCHHHHHHCCCHHHHHHHHH----HCCCCEEEC--CHHHHHHHHHHHH-HHHHHCCC-C Q ss_conf 9999999986235-8--504117488752565034334543----044310003--7245568888521-43311168-8 Q gi|254780696|r 98 YITSTYLLEKINP-E--TLIVNNPFWIRNSPEKIFVTEFSE----LMPPTLISR--DITQITRFYLEMK-DIIIKPLY-G 166 (316) Q Consensus 98 yi~~~~~Le~~~~-~--~~viN~p~~i~~~~eKl~~~~~~~----~~P~T~vt~--~~~~~~~f~~~~~-~vViKPl~-g 166 (316) T Consensus 72 hv~~~-~L~~L~~~g~~~~~~P~~~~l~~~~dk~~qK~~L~~~g~~vp~f~~~~~~~~~~~~~~~~~~g~p~VlK~~~gG 150 (386) T TIGR01161 72 HVDVE-ALEKLEARGDKVKVRPSPEALAIIQDKLTQKQFLQKLGLPVPPFVVIEIKDEEELDSALQELGFPVVLKARRGG 150 (386) T ss_pred CCCCH-HHHHHHHCCCEEEEECCHHHHHHHHCHHHHHHHHHHCCCCCCCCCEEECCCHHHHHHHHHHCCCCEEEEEEECC T ss_conf 37856-78999835984776038899998836589999999668998841202236842578999873984799842065 Q ss_pred CCCCCEEEECCCCCCHHHHHHHHHHHCCCCCCEEECCCCCCCCCEEEEEE---CCEEEEEEEEECCCCCCCCCCCCC--C Q ss_conf 54344687448871158899999840013340021053445682699998---998863212204568600000014--7 Q gi|254780696|r 167 NGGTGVFRITLGDRNFSSLIEMLFEKYPEPLMIQSYLPQIRDGDKRILLL---NGKPVGAVNRIPSEVDNRSNIHAG--G 241 (316) Q Consensus 167 ~~G~gV~~i~~~~~~~~~~~e~~~~~~~~~ii~Qefi~~~~~gD~Rv~vi---~g~~v~a~~R~~~~~~~r~Nl~~G--g 241 (316) T Consensus 151 YDGrGq~~i~-~~~~~~~~~~~~~~~-~~~~~~E~fV~--F~~Elsv~vaR~~~G~~~~----YP~----ven~~~ddag 218 (386) T TIGR01161 151 YDGRGQFVIK-SEADLPQALKELGDK-EEELIVEEFVP--FERELSVIVARSADGEIAF----YPV----VENIHQDDAG 218 (386) T ss_pred CCCCCCEEEC-CHHHHHHHHHHCCCC-CEEEEEEECCC--CCEEEEEEEEECCCCCEEE----CCC----EEEEEECCCC T ss_conf 2773108974-743288999852888-40589852356--2006999999778974888----286----1235652778 Q ss_pred C----EEEE-ECCHHH---HHHHHHHHHHHHHCCCEEEEE Q ss_conf 3----1110-077899---999999999999849879999 Q gi|254780696|r 242 K----AELT-KLTKID---LDICKRIGESLRERGLFFTGI 273 (316) Q Consensus 242 ~----~~~~-~lt~~~---~~i~~~~~~~L~~~gl~~~Gi 273 (316) T Consensus 219 Il~~~~aPAPa~p~~~~Q~~~~A~~~A~~~~~-~L~~VG~ 257 (386) T TIGR01161 219 ILRLVVAPAPAVPDALVQQQKKAQELARRLAE-ELDYVGV 257 (386) T ss_pred EEEEEEECCCCCCHHHHHHHHHHHHHHHHHHH-HCCCEEE T ss_conf 77898633777834578999999999999998-6196178

HHsearch alignment for GI: 254780696 and conserved domain: TIGR01161