SpuA native structure

Experimental Data Snapshot

  • Resolution: 1.60 Å
  • R-Value Free: 0.231 
  • R-Value Work: 0.191 
  • R-Value Observed: 0.192 

Starting Model: experimental
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Structure and mechanism of the gamma-glutamyl-gamma-aminobutyrate hydrolase SpuA from Pseudomonas aeruginosa.

Chen, Y.Jia, H.Zhang, J.Liang, Y.Liu, R.Zhang, Q.Bartlam, M.

(2021) Acta Crystallogr D Struct Biol 77: 1305-1316

  • DOI: https://doi.org/10.1107/S2059798321008986
  • Primary Citation of Related Structures:  
    7D4R, 7D50, 7D53, 7D54

  • PubMed Abstract: 

    Polyamines are important regulators in all living organisms and are implicated in essential biological processes including cell growth, differentiation and apoptosis. Pseudomonas aeruginosa possesses an spuABCDEFGHI gene cluster that is involved in the metabolism and uptake of two polyamines: spermidine and putrescine. In the proposed γ-glutamylation-putrescine metabolism pathway, SpuA hydrolyzes γ-glutamyl-γ-aminobutyrate (γ-Glu-GABA) to glutamate and γ-aminobutyric acid (GABA). In this study, crystal structures of P. aeruginosa SpuA are reported, confirming it to be a member of the class I glutamine amidotransferase (GAT) family. Activity and substrate-binding assays confirm that SpuA exhibits a preference for γ-Glu-GABA as a substrate. Structures of an inactive H221N mutant were determined with bound glutamate thioester intermediate or glutamate product, thus delineating the active site and substrate-binding pocket and elucidating the catalytic mechanism. The crystal structure of another bacterial member of the class I GAT family from Mycolicibacterium smegmatis (MsGATase) in complex with glutamine was determined for comparison and reveals a binding site for glutamine. Activity assays confirm that MsGATase has activity for glutamine as a substrate but not for γ-Glu-GABA. The work reported here provides a starting point for further investigation of polyamine metabolism in P. aeruginosa.

  • Organizational Affiliation

    State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Protein Science and College of Life Sciences, Nankai University, Tianjin 300071, People's Republic of China.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Probable glutamine amidotransferase
A, B
250Pseudomonas aeruginosa PAO1Mutation(s): 0 
Gene Names: spuAPA0297
Find proteins for Q9I6J4 (Pseudomonas aeruginosa (strain ATCC 15692 / DSM 22644 / CIP 104116 / JCM 14847 / LMG 12228 / 1C / PRS 101 / PAO1))
Explore Q9I6J4 
Go to UniProtKB:  Q9I6J4
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9I6J4
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.60 Å
  • R-Value Free: 0.231 
  • R-Value Work: 0.191 
  • R-Value Observed: 0.192 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 47.769α = 90
b = 72.625β = 98.986
c = 63.774γ = 90
Software Package:
Software NamePurpose
HKL-3000data reduction
HKL-3000data scaling

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
National Natural Science Foundation of China (NSFC)China31870053
National Natural Science Foundation of China (NSFC)China31800627

Revision History  (Full details and data files)

  • Version 1.0: 2021-10-06
    Type: Initial release
  • Version 1.1: 2021-10-13
    Changes: Database references
  • Version 1.2: 2021-10-20
    Changes: Database references
  • Version 1.3: 2023-11-29
    Changes: Data collection, Refinement description