>TIGR01855 IMP_synth_hisH imidazole glycerol phosphate synthase, glutamine amidotransferase subunit; InterPro: IPR010139 Imidazole glycerol phosphate synthetase (IGPS) is a key metabolic enzyme, which links amino acid and nucleotide biosynthesis: it catalyses the closure of the imidazole ring within histidine biosynthesis (fifth step), and provides the substrate for de novo purine biosynthesis. IGPS consists of two different subunits: HisH, a glutamine amidotransferase (glutaminase), and HisF, a synthase (cyclase). HisH functions to provide a source of nitrogen, which is required for the synthesis of histidine and purines. In the HisH glutaminase reaction, the hydrolysis of glutamine yields ammonia, which is then used by HisF in the subsequent synthase reaction. The X-ray structure of the HisH/HisF heterodimer of IGPS reveals a putative tunnel for the transfer of ammonia from HisH to HisF via a (beta-alpha)8 barrel fold within HisF that abuts HisH . Ammonia tunnels connect the glutaminase and synthase active sites. HisH belongs to a large group of enzymes found in diverse and fundamental anabolic pathways. These enzymes share a common domain, referred to as the type-I glutamine amidotransferase (GATase) domain, which can occur either as single polypeptides (as with HisH) or as domains of large multifunctional proteins.; GO: 0016763 transferase activity transferring pentosyl groups, 0000105 histidine biosynthetic process, 0005737 cytoplasm.

Probab=99.76 E-value=2.7e-18 Score=137.85 Aligned_cols=172 Identities=22% Similarity=0.391 Sum_probs=116.4 Q ss_pred HHHHHHHHHHCCCCEEEEECCC-CCCCCCCEEEECC-CCCCCCCCCHHHHHHHHHHHHHHHHHHHCCCEEEEECCCHHHH Q ss_conf 9999999985499639982154-6445647899728-7345431140677520021212233220597178606403101 Q gi|254780971|r 15 NDMIKAITKIIGQSPILVWQSD-TDIPDVDLIVIPG-GFSYGDYLRCGAIAARTPVMQAIKKKAQQGIKVMGICNGFQIL 92 (219) Q Consensus 15 ~e~~~A~~~~~~~~~~~v~~~~-~~l~~~d~lvipG-GFSygD~l~aG~i~~~~~~~~~i~~~~~~g~~vLGICNGfQiL 92 (219) T Consensus 16 rGV~~Al~~-~G~~~~v-~~~~y~~~~~aD~l~LPGVG-~F~~aM---~~l~~~~~~~~~~~~~~~~~P~lGiCLGMQLL 89 (211) T TIGR01855 16 RGVKRALKR-VGAEPVV-VKDSYKELEKADKLILPGVG-AFKAAM---ARLRELGLLDLLELVVKKKKPVLGICLGMQLL 89 (211) T ss_pred HHHHHHHHH-CCCEEEE-ECCCCHHHHCCCEEEECCCC-CHHHHH---HHHHHHHHHHHHHHHHHCCCCEEEEEHHHHHH T ss_conf 999999984-4981799-62860343106867857858-889999---99885005878899996189689998023430 Q ss_pred EE-----------CCCHHHH---HCCCCCCC----EEEEEEEEEECCCHHHHHHHCCCCCEEEEEEECCCEEEEECHHHH Q ss_conf 00-----------0001011---01244332----454225767525235776413799689986201330233086774 Q gi|254780971|r 93 VE-----------LNLLPGI---LMRNCSLK----FVCKQVLLEVVNSNTAFTKSYKMNQIIKCPVAHHDGNYFIDAKGL 154 (219) Q Consensus 93 ~e-----------lGLlPg~---l~~N~s~r----f~~r~~~~~v~~~~s~~~~~~~~~~~l~~piaHgEGrf~~~~~~l 154 (219) T Consensus 90 fe~SeE~g~~~~GLG~i~G~V~k~~~~~~~~~lk~PHmGWN~v~~~~~~C~ll~g~~~~~-----------~~YFVHSY~ 158 (211) T TIGR01855 90 FERSEEGGGEVPGLGLIKGKVVKLEARVSLSKLKVPHMGWNEVEPVKESCPLLKGIDKGA-----------YFYFVHSYY 158 (211) T ss_pred HCCCCCCCCCCCCCEECCCEEEEECCCCCCCCCCCCCCCCCEEEEHHHCCCHHCCCCCCC-----------CEEEEEEEE T ss_conf 015624378866531127613420567788725457565642312311551130776678-----------155688667 Q ss_pred HHHHHC--CEEE-EECCCCCCCCCCCCCEEEEECCCCCEEEECCCCHHHCCCCCCCCCHHHHHHHHCC Q ss_conf 115422--5036-5316888889881126688869998999848843432210067762899986429 Q gi|254780971|r 155 AEIEKN--NQIV-FRYASGTNPNGSLHDIAGVINRRGNVLGMMPHPENIIEKFHGGIDGRGLFASLLT 219 (219) Q Consensus 155 ~~l~~~--~~i~-~~Y~d~~NPNGS~~~IAgi~s~~G~vlgmMPHPER~~~~~~~~~dG~~~f~~~~s 219 (219) T Consensus 159 ~~~~~~S~~v~a~~~YG~~F--------~AaV--~~~n~~G~QFHPEKS~~~------G~~lL~nf~~ 210 (211) T TIGR01855 159 AVCEEESEAVLAKADYGEKF--------TAAV--QKDNIFGTQFHPEKSGKT------GLKLLKNFLE 210 (211) T ss_pred EECCCCHHHEEEEHHCCCCE--------EEEE--ECCCEEEEEECCHHHHHH------HHHHHHHHHC T ss_conf 76168811501120018630--------4466--548789997285688889------9999999852

HHsearch alignment for GI: 254780971 and conserved domain: TIGR01855