Sandbox Reserved 349: Difference between revisions
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Porphobilinogen deaminase (PBGD) also known as Hydroxymethylbilane synthase, is a monomeric polypeptide and is the third enzyme in the heme biosynthesis pathways in mammals<ref name="Raj">PMID: 19207107</ref>. It catalyses the polymerization of four porphobilinogen molecules to yield hydroxymethylbilane, a precursor in the formation of [[Porphyrin]]<ref name="Peter">PMID:3079571</ref>. Porphobilinogen deaminases are able to form surprisingly stable enzyme-substrate complexes with up to four pyrrole substrates interacting with the active site, a feature unique to the group of enzymes<ref name="Anderson">PMID:7354069</ref>. <scene name='Sandbox_Reserved_349/Dpm/2'>Dipyrromethane (DPM)</scene>, a cofactor unique to porphobilinogen deaminases, is thought to stabilize these interactions at each of the two active domains<ref name="Peter">PMID:3079571</ref>. Mutations in the human PBGD (hPBGD) gene are responsible for the condition Acute Intermittent Porphyria (AIP) in humans<ref name="Raj">PMID: 19207107</ref>. | Porphobilinogen deaminase (PBGD) also known as Hydroxymethylbilane synthase, is a monomeric polypeptide and is the third enzyme in the heme biosynthesis pathways in mammals<ref name="Raj">PMID: 19207107</ref>. It catalyses the polymerization of four porphobilinogen molecules to yield hydroxymethylbilane, a precursor in the formation of [[Porphyrin]]<ref name="Peter">PMID:3079571</ref>. Porphobilinogen deaminases are able to form surprisingly stable enzyme-substrate complexes with up to four pyrrole substrates interacting with the active site, a feature unique to the group of enzymes<ref name="Anderson">PMID:7354069</ref>. <scene name='Sandbox_Reserved_349/Dpm/2'>Dipyrromethane (DPM)</scene>, a cofactor unique to porphobilinogen deaminases, is thought to stabilize these interactions at each of the two active domains<ref name="Peter">PMID:3079571</ref>. Mutations in the human PBGD (hPBGD) gene are responsible for the condition Acute Intermittent Porphyria (AIP) in humans<ref name="Raj">PMID: 19207107</ref>. | ||
=Porphobilinogen deaminase= | =Porphobilinogen deaminase= | ||
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==Structure== | ==Structure== | ||
PBGD is a monomeric three-domain polypeptide with each domain consisting of approximately 110 amino acids. The human variant has an additional 29 residue loop in domain three that extends hydrogen bonding across domains one and three while ''E.coli'' PBGD is lacking this extended loop <ref name="Raj">PMID: 19207107</ref>. In the active site, a unique molecule known as <scene name='Template:Sandbox_Reserved_349/Dpm_site/2'>Dipyrromethane</scene> interacts with porphobilinogen and anchors it in place<ref name="Raj">PMID: 19207107</ref>. Ordered <scene name='Sandbox_Reserved_349/So4_hbond/1'>sulfate ions</scene> are also hydrogen bonded with Arg26 and Ser28 residues near the active site that are highly conserved amongst human and ''E.coli'' variants of PBGD<ref name="Raj">PMID: 19207107</ref>. | PBGD is a monomeric three-domain polypeptide with each domain consisting of approximately 110 amino acids. The human variant has an additional 29 residue loop in domain three that extends hydrogen bonding across domains one and three while ''E.coli'' PBGD is lacking this extended loop <ref name="Raj">PMID: 19207107</ref>. In the active site, a unique molecule known as <scene name='Template:Sandbox_Reserved_349/Dpm_site/2'>Dipyrromethane</scene> interacts with porphobilinogen and anchors it in place<ref name="Raj">PMID: 19207107</ref>. Ordered <scene name='Sandbox_Reserved_349/So4_hbond/1'>sulfate ions</scene> are also hydrogen bonded with Arg26 and Ser28 residues near the active site that are highly conserved amongst human and ''E.coli'' variants of PBGD<ref name="Raj">PMID: 19207107</ref>. | ||
