1INL: Crystal Structure Of Spermidine Synthase From Thermotoga Maritima

Polyamines are essential in all branches of life. Spermidine synthase (putrescine aminopropyltransferase, PAPT) catalyzes the biosynthesis of spermidine, a ubiquitous polyamine. The crystal structure of the PAPT from Thermotoga maritima (TmPAPT) has been solved to 1.5 A resolution in the presence and absence of AdoDATO (S-adenosyl-1,8-diamino-3-thiooctane), a compound containing both substrate and product moieties. This, the first structure of an aminopropyltransferase, reveals deep cavities for binding substrate and cofactor, and a loop that envelops the active site. The AdoDATO binding site is lined with residues conserved in PAPT enzymes from bacteria to humans, suggesting a universal catalytic mechanism. Other conserved residues act sterically to provide a structural basis for polyamine specificity. The enzyme is tetrameric; each monomer consists of a C-terminal domain with a Rossmann-like fold and an N-terminal beta-stranded domain. The tetramer is assembled using a novel barrel-type oligomerization motif.
PDB ID: 1INLDownload
MMDB ID: 17933
PDB Deposition Date: 2001/5/14
Updated in MMDB: 2001/12
Experimental Method:
x-ray diffraction
Resolution: 1.5  Å
Source Organism:
Similar Structures:
Biological Unit for 1INL: tetrameric; determined by author and by software (PISA)
Molecular Components in 1INL
Label Count Molecule
Proteins (4 molecules)
Spermidine Synthase(Gene symbol: TM0654)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB