>gnl|CDD|88600 cd04824, eu_ALAD_PBGS_cysteine_rich, Porphobilinogen synthase (PBGS), which is also called delta-aminolevulinic acid dehydratase (ALAD), catalyzes the condensation of two 5-aminolevulinic acid (ALA) molecules to form the pyrrole porphobilinogen (PBG), which is the second step in the biosynthesis of tetrapyrroles, such as heme, vitamin B12 and chlorophyll. This reaction involves the formation of a Schiff base link between the substrate and the enzyme. PBGSs are metalloenzymes, some of which have a second, allosteric metal binding site, beside the metal ion binding site in their active site. Although PBGS is a family of homologous enzymes, its metal ion utilization at catalytic site varies between zinc and magnesium and/or potassium. PBGS can be classified into two groups based on differences in their active site metal binding site. The eukaryotic PBGSs represented by this model, which contain a cysteine-rich zinc binding motif (DXCXCX(Y/F)X3G(H/Q)CG), require zinc for their activity, they do not contain an additional allosteric metal binding site and do not bind magnesium.. Length = 320

Score = 252 bits (645), Expect = 1e-67 Identities = 120/308 (38%), Positives = 176/308 (57%), Gaps = 7/308 (2%) Query: 27 REMVREHRLSVSDLILPIFLTSGEKTVESINSMPDVMRMSIDVAVEKIKQVADLGIPAIA 86 R+ E L+ S+LI PIF+T + I+S+P + R ++ E ++ + G+ ++ Sbjct: 10 RQWQSERTLTKSNLIYPIFITDNPDAKQPIDSLPGINRYGVNRLEEFLRPLVAKGLRSVI 69 Query: 87 IF--PNIPMDLRNNTGSHIIDPDNLINEGICAIKKNIPNIGIITDVALDPFTIHGHDGIL 144 +F P P + +GS D D + + I I++ P + I DV L +T HGH GIL Sbjct: 70 LFGVPLKPGK-DDRSGSAADDEDGPVIQAIKLIREEFPELLIACDVCLCEYTSHGHCGIL 128 Query: 145 -CDGEIVNDETIELISHAAVIQADAGADIIAPSEMMDGRVQEIRKKLDSHGHIN-VGIMP 202 DG I N+ +++ ++ A+ A AGA I+APS+MMDGRV+ I++ L G N V +M Sbjct: 129 YEDGTINNEASVKRLAEVALAYAKAGAHIVAPSDMMDGRVRAIKQALIQAGLGNKVSVMS 188 Query: 203 YVAKFNSSFYGPYRDAISTRDLLKGDKKTYYLDPANVQEAIREASIDIQESADMLLVKPG 262 Y AKF S YGP+RDA + GD++ Y L P A+R D+ E ADM++VKPG Sbjct: 189 YSAKFASCLYGPFRDAACSAPS-FGDRRCYQLPPGARGLALRAVERDVSEGADMIMVKPG 247 Query: 263 LPYLDVCFRIKEKFG-LPTFAYQVSGEYAMIKAASLQGWINKNDAMMESLLAFKRAGCDG 321 PYLD+ K+K LP Y VSGEYAM+ AA+ G + A++E++ F+RAG D Sbjct: 248 TPYLDIVREAKDKHPDLPLAVYHVSGEYAMLHAAAEAGAFDLKRAVLEAMTGFRRAGADI 307 Query: 322 IFTYFAME 329 I TYF E Sbjct: 308 IITYFTPE 315

RPSBLAST alignment for GI: 255764463 and conserved domain: cd04824