1S5K: Aminoglycoside N-Acetyltransferase Aac(6')-Iy In Complex With Coa And N-Terminal His(6)-Tag (Crystal Form 1)

The Salmonella enterica chromosomally encoded AAC(6')-Iy has been shown to confer broad aminoglycoside resistance in strains in which the structural gene is expressed. The three-dimensional structures reported place the enzyme in the large Gcn5-related N-acetyltransferase (GNAT) superfamily. The structure of the CoA-ribostamycin ternary complex allows us to propose a chemical mechanism for the reaction, and comparison with the Mycobacterium tuberculosis AAC(2')-CoA-ribostamycin complex allows us to define how regioselectivity of acetylation is achieved. The AAC(6')-Iy dimer is most structurally similar to the Saccharomyces cerevisiae Hpa2-encoded histone acetyltransferase. We demonstrate that AAC(6')-Iy catalyzes both acetyl-CoA-dependent self-alpha-N-acetylation and acetylation of eukaryotic histone proteins and the human histone H3 N-terminal peptide. These structural and catalytic similarities lead us to propose that chromosomally encoded bacterial acetyltransferases, including those functionally identified as aminoglycoside acetyltransferases, are the evolutionary progenitors of the eukaryotic histone acetyltransferases.
PDB ID: 1S5KDownload
MMDB ID: 27784
PDB Deposition Date: 2004/1/21
Updated in MMDB: 2007/10
Experimental Method:
x-ray diffraction
Resolution: 2.4  Å
Source Organism:
Similar Structures:
Biological Unit for 1S5K: dimeric; determined by author and by software (PISA)
Molecular Components in 1S5K
Label Count Molecule
Proteins (2 molecules)
Aminoglycoside 6'-n-acetyltransferase
Molecule annotation
Chemicals (4 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB