3SGC image
Entry Detail
PDB ID:
3SGC
Keywords:
Title:
Crystal Structure of Apo Aminoglycoside-2''-Phosphotransferase Type IVa
Biological Source:
Host Organism:
PDB Version:
Deposition Date:
2011-06-14
Release Date:
2011-06-29
Method Details:
Experimental Method:
Resolution:
2.05 Å
R-Value Free:
0.26
R-Value Work:
0.21
R-Value Observed:
0.22
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:APH(2'')-Id
Chain IDs:A
Chain Length:302
Number of Molecules:1
Biological Source:Enterococcus casseliflavus
Primary Citation
Crystal Structures of Antibiotic-Bound Complexes of Aminoglycoside 2''-Phosphotransferase IVa Highlight the Diversity in Substrate Binding Modes among Aminoglycoside Kinases.
Biochemistry 50 6237 6244 (2011)
PMID: 21678960 DOI: 10.1021/bi200747f

Abstact

Aminoglycoside 2''-phosphotransferase IVa [APH(2'')-IVa] is a member of a family of bacterial enzymes responsible for medically relevant resistance to antibiotics. APH(2'')-IVa confers high-level resistance against several clinically used aminoglycoside antibiotics in various pathogenic Enterococcus species by phosphorylating the drug, thereby preventing it from binding to its ribosomal target and producing a bactericidal effect. We describe here three crystal structures of APH(2'')-IVa, one in its apo form and two in complex with a bound antibiotic, tobramycin and kanamycin A. The apo structure was refined to a resolution of 2.05 Å, and the APH(2'')-IVa structures with tobramycin and kanamycin A bound were refined to resolutions of 1.80 and 2.15 Å, respectively. Comparison among the structures provides insight concerning the substrate selectivity of this enzyme. In particular, conformational changes upon substrate binding, involving rotational shifts of two distinct segments of the enzyme, are observed. These substrate-induced shifts may also rationalize the altered substrate preference of APH(2'')-IVa in comparison to those of other members of the APH(2'') subfamily, which are structurally closely related. Finally, analysis of the interactions between the enzyme and aminoglycoside reveals a distinct binding mode as compared to the intended ribosomal target. The differences in the pattern of interactions can be utilized as a structural basis for the development of improved aminoglycosides that are not susceptible to these resistance factors.

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