CATH Domain 3eq1A01

CATH Classification

Level	CATH Code	Description
	3	Alpha Beta
	3.40	3-Layer(aba) Sandwich
	3.40.190	D-Maltodextrin-Binding Protein; domain 2
	3.40.190.10	Periplasmic binding protein-like II

Domain Context

CATH Clusters

Superfamily	Periplasmic binding protein-like II
Functional Family	Porphobilinogen deaminase

Enzyme Information

2.5.1.61

Hydroxymethylbilane synthase.

based on mapping to UniProt P08397

4 porphobilinogen + H(2)O = hydroxymethylbilane + 4 NH(3).

-!- The enzyme works by stepwise addition of pyrrolylmethyl groups until a hexapyrrole is present at the active center. -!- The terminal tetrapyrrole is then hydrolyzed to yield the product, leaving a cysteine-bound dipyrrole on which assembly continues. -!- In the presence of a second enzyme, EC 4.2.1.75, which is often called cosynthase, the product is cyclized to form uroporphyrinogen III. -!- If EC 4.2.1.75 is absent, the hydroxymethylbilane cyclizes spontaneously to form uroporphyrinogen I. -!- Formerly EC 4.3.1.8.

UniProtKB Entries (1)

P08397

HEM3_HUMAN

Homo sapiens

Porphobilinogen deaminase

PDB Structure

PDB	3EQ1
External Links	PDBSum Proteopedia
Method	X-RAY DIFFRACTION
Organism
Primary Citation	Structure of human porphobilinogen deaminase at 2.8 A: the molecular basis of acute intermittent porphyria Gill, R., Kolstoe, S.E., Mohammed, F., Al D-Bass, A., Mosely, J.E., Sarwar, M., Cooper, J.B., Wood, S.P., Shoolingin-Jordan, P.M. Biochem.J.