4QC6 image
Entry Detail
PDB ID:
4QC6
Title:
Crystal structure of aminoglycoside 6'-acetyltransferase-Ie
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2014-05-09
Release Date:
2014-10-22
Method Details:
Experimental Method:
Resolution:
1.30 Å
R-Value Free:
0.16
R-Value Work:
0.14
R-Value Observed:
0.14
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Bifunctional AAC/APH
Chain IDs:A, B
Chain Length:179
Number of Molecules:2
Biological Source:Staphylococcus warneri
Primary Citation
Structure of the bifunctional aminoglycoside-resistance enzyme AAC(6')-Ie-APH(2'')-Ia revealed by crystallographic and small-angle X-ray scattering analysis.
Acta Crystallogr.,Sect.D 70 2754 2764 (2014)
PMID: 25286858 DOI: 10.1107/S1399004714017635

Abstact

Broad-spectrum resistance to aminoglycoside antibiotics in clinically important Gram-positive staphylococcal and enterococcal pathogens is primarily conferred by the bifunctional enzyme AAC(6')-Ie-APH(2'')-Ia. This enzyme possesses an N-terminal coenzyme A-dependent acetyltransferase domain [AAC(6')-Ie] and a C-terminal GTP-dependent phosphotransferase domain [APH(2'')-Ia], and together they produce resistance to almost all known aminoglycosides in clinical use. Despite considerable effort over the last two or more decades, structural details of AAC(6')-Ie-APH(2'')-Ia have remained elusive. In a recent breakthrough, the structure of the isolated C-terminal APH(2'')-Ia enzyme was determined as the binary Mg2GDP complex. Here, the high-resolution structure of the N-terminal AAC(6')-Ie enzyme is reported as a ternary kanamycin/coenzyme A abortive complex. The structure of the full-length bifunctional enzyme has subsequently been elucidated based upon small-angle X-ray scattering data using the two crystallographic models. The AAC(6')-Ie enzyme is joined to APH(2'')-Ia by a short, predominantly rigid linker at the N-terminal end of a long α-helix. This α-helix is in turn intrinsically associated with the N-terminus of APH(2'')-Ia. This structural arrangement supports earlier observations that the presence of the intact α-helix is essential to the activity of both functionalities of the full-length AAC(6')-Ie-APH(2'')-Ia enzyme.

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