Crystal structure of Y145F mutant of KacT

Experimental Data Snapshot

  • Resolution: 2.00 Å
  • R-Value Free: 0.247 
  • R-Value Work: 0.205 
  • R-Value Observed: 0.207 

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Identification and characterization of acetyltransferase-type toxin-antitoxin locus in Klebsiella pneumoniae

Qian, H.Yao, Q.Tai, C.Deng, Z.Gan, J.Ou, H.Y.

(2018) Mol Microbiol 108: 336-349

  • DOI: https://doi.org/10.1111/mmi.13934
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    A type II toxin-antitoxin (TA) system, in which the toxin contains a Gcn5-related N-acetyltransferase (GNAT) domain, has been characterized recently. GNAT toxin acetylates aminoacyl-tRNA and blocks protein translation. It is abolished by the cognate antitoxin that contains the ribbon-helix-helix (RHH) domain. Here, we present an experimental demonstration of the interaction of the GNAT-RHH complex with TA promoter DNA. First, the GNAT-RHH TA locus kacAT was found in Klebsiella pneumoniae HS11286, a strain resistant to multiple antibiotics. Overexpression of KacT halted cell growth and resulted in persister cell formation. The crystal structure also indicated that KacT is a typical acetyltransferase toxin. Co-expression of KacA neutralized KacT toxicity. Expression of the bicistronic kacAT locus was up-regulated during antibiotic stress. Finally, KacT and KacA formed a heterohexamer that interacted with promoter DNA, resulting in negative autoregulation of kacAT transcription. The N-terminus region of KacA accounted for specific binding to the palindromic sequence on the operator DNA, whereas its C-terminus region was essential for the inactivation of the GNAT toxin. These results provide an important insight into the regulation of the GNAT-RHH family TA system.

  • Organizational Affiliation

    State Key Laboratory of Microbial Metabolism, Joint International Laboratory on Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, China.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
177Klebsiella pneumoniaeMutation(s): 1 
Gene Names: AGG09_10975BB749_24230BL127_018840BL143_022465
Find proteins for A6THQ8 (Klebsiella pneumoniae subsp. pneumoniae (strain ATCC 700721 / MGH 78578))
Explore A6THQ8 
Go to UniProtKB:  A6THQ8
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA6THQ8
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.00 Å
  • R-Value Free: 0.247 
  • R-Value Work: 0.205 
  • R-Value Observed: 0.207 
  • Space Group: P 31 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 52.869α = 90
b = 52.869β = 90
c = 255.296γ = 120
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
Ministry of Science and TechnologyChina2015CB554202

Revision History  (Full details and data files)

  • Version 1.0: 2017-07-19
    Type: Initial release
  • Version 1.1: 2019-01-30
    Changes: Data collection, Database references
  • Version 1.2: 2023-11-22
    Changes: Data collection, Database references, Refinement description