2B5G

Wild Type SSAT- 1.7A structure


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.211 

wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Structures of wild-type and mutant human spermidine/spermine N1-acetyltransferase, a potential therapeutic drug target

Bewley, M.C.Graziano, V.Jiang, J.S.Matz, E.Studier, F.W.Pegg, A.P.Coleman, C.S.Flanagan, J.M.

(2006) Proc Natl Acad Sci U S A 103: 2063-2068

  • DOI: 10.1073/pnas.0511008103
  • Primary Citation of Related Structures:  
    2B3V, 2B3U, 2B4B, 2B58, 2B4D, 2B5G

  • PubMed Abstract: 
  • Spermidine/spermine N1-acetyltransferase (SSAT) is a key enzyme in the control of polyamine levels in human cells, as acetylation of spermidine and spermine triggers export or degradation. Increased intracellular polyamine levels accompany several types of cancers as well as other human diseases, and compounds that affect the expression, activity, or stability of SSAT are being explored as potential therapeutic drugs ...

    Spermidine/spermine N1-acetyltransferase (SSAT) is a key enzyme in the control of polyamine levels in human cells, as acetylation of spermidine and spermine triggers export or degradation. Increased intracellular polyamine levels accompany several types of cancers as well as other human diseases, and compounds that affect the expression, activity, or stability of SSAT are being explored as potential therapeutic drugs. We have expressed human SSAT from the cloned cDNA in Escherichia coli and have determined high-resolution structures of wild-type and mutant SSAT, as the free dimer and in binary and ternary complexes with CoA, acetyl-CoA (AcCoA), spermine, and the inhibitor N1,N11bis-(ethyl)-norspermine (BE-3-3-3). These structures show details of binding sites for cofactor, substrates, and inhibitor and provide a framework to understand enzymatic activity, mutations, and the action of potential drugs. Two dimer conformations were observed: a symmetric form with two open surface channels capable of binding substrate or cofactor, and an asymmetric form in which only one of the surface channels appears capable of binding and acetylating polyamines. SSAT was found to self-acetylate lysine-26 in the presence of AcCoA and absence of substrate, a reaction apparently catalzyed by AcCoA bound in the second channel of the asymmetric dimer. These unexpected and intriguing complexities seem likely to have some as yet undefined role in regulating SSAT activity or stability as a part of polyamine homeostasis. Sequence signatures group SSAT with proteins that appear to have thialysine Nepsilon-acetyltransferase activity.


    Organizational Affiliation

    Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Diamine acetyltransferase 1A171Homo sapiensMutation(s): 0 
Gene Names: SATSAT1
EC: 2.3.1.57
UniProt & NIH Common Fund Data Resources
Find proteins for P21673 (Homo sapiens)
Explore P21673 
Go to UniProtKB:  P21673
PHAROS:  P21673
Protein Feature View
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Diamine acetyltransferase 1B171N/AMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for P21673 (Homo sapiens)
Explore P21673 
Go to UniProtKB:  P21673
PHAROS:  P21673
Protein Feature View
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  • Reference Sequence
Small Molecules
Modified Residues  2 Unique
IDChainsTypeFormula2D DiagramParent
MSE
Query on MSE
AL-PEPTIDE LINKINGC5 H11 N O2 SeMET
ALY
Query on ALY
BL-PEPTIDE LINKINGC8 H16 N2 O3LYS
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.211 
  • Space Group: P 43
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 74.212α = 90
b = 74.212β = 90
c = 63.077γ = 90
Software Package:
Software NamePurpose
CNSrefinement

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2006-01-17
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2021-02-03
    Changes: Derived calculations, Structure summary