5XUN

Crystal structure of Y145F mutant of KacT

Summary for 5XUN

• Entry DOI: 10.2210/pdb5xun/pdb
• Descriptor: Acetyltransferase, ACETYL COENZYME *A, ACETATE ION, ... (4 entities in total)
• Functional Keywords: klebsiella pneumoniae, toxin
• Biological source: Klebsiella pneumoniae
• Total number of polymer chains: 2
• Total formula weight: 41363.49

Authors

Qian, H.L.,Yao, Q.Q.,Gan, J.H.,Ou, H.Y. (deposition date: 2017-06-23, release date: 2017-07-19, Last modification date: 2023-11-22)

Primary citation

Qian, H.,Yao, Q.,Tai, C.,Deng, Z.,Gan, J.,Ou, H.Y.
Identification and characterization of acetyltransferase-type toxin-antitoxin locus in Klebsiella pneumoniae
Mol. Microbiol., 108:336-349, 2018

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.

PubMed: 29461656
DOI: 10.1111/mmi.13934

Experimental method

X-RAY DIFFRACTION (2 Å)