1PV8 image
Deposition Date 2003-06-26
Release Date 2003-09-09
Last Version Date 2024-12-25
Entry Detail
PDB ID:
1PV8
Keywords:
Title:
Crystal structure of a low activity F12L mutant of human porphobilinogen synthase
Biological Source:
Source Organism:
Homo sapiens (Taxon ID: 9606)
Host Organism:
Method Details:
Experimental Method:
Resolution:
2.20 Å
R-Value Free:
0.28
R-Value Work:
0.19
R-Value Observed:
0.19
Space Group:
P 63
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:Delta-aminolevulinic acid dehydratase
Gene (Uniprot):ALAD
Mutations:F12L
Chain IDs:A, B
Chain Length:330
Number of Molecules:2
Biological Source:Homo sapiens
Primary Citation
Control of tetrapyrrole biosynthesis by alternate quaternary forms of porphobilinogen synthase.
Nat.Struct.Biol. 10 757 763 (2003)
PMID: 12897770 DOI: 10.1038/nsb963

Abstact

Porphobilinogen synthase (PBGS) catalyzes the first common step in the biosynthesis of tetrapyrroles (such as heme and chlorophyll). Although the predominant oligomeric form of this enzyme, as inferred from many crystal structures, is that of a homo-octamer, a rare human PBGS allele, F12L, reveals the presence of a hexameric form. Rearrangement of an N-terminal arm is responsible for this oligomeric switch, which results in profound changes in kinetic behavior. The structural transition between octamer and hexamer must proceed through an unparalleled equilibrium containing two different dimer structures. The allosteric magnesium, present in most PBGS, has a binding site in the octamer but not in the hexamer. The unprecedented structural rearrangement reported here relates to the allosteric regulation of PBGS and suggests that alternative PBGS oligomers may function in a magnesium-dependent regulation of tetrapyrrole biosynthesis in plants and some bacteria.

Legend

Protein

Chemical

Disease

Primary Citation of related structures