PDBsum entry 3n4u

Unknown function

PDB id: 3n4u

Contents

Protein chain

301 a.a. *

Waters ×232

* Residue conservation analysis

PDB id:

3n4u

Name:

Unknown function

Title:

App aph(2")-iva form ii

Structure:

Aph(2'')-id. Chain: a. Engineered: yes

Source:

Enterococcus casseliflavus. Enterococcus flavescens. Organism_taxid: 37734. Gene: aph(2'')-id

Resolution:

2.20Å R-factor: 0.183 R-free: 0.273

Authors:

C.A.Smith,M.Toth,H.Frase,S.B.Vakulenko

Key ref:

M.Toth et al. (2010). Crystal structure and kinetic mechanism of aminoglycoside phosphotransferase-2''-IVa. Protein Sci, 19, 1565-1576. PubMed id: 20556826

Date:

22-May-10 Release date: 30-Jun-10

Protein chain

O68183  (O68183_ENTCA) -  APH(2'')-Id from Enterococcus casseliflavus

Seq: 301 a.a.

Struc: 301 a.a.

Enzyme reactions

• Enzyme class: E.C.?

Protein Sci 19:1565-1576 (2010)

PubMed id: 20556826

Crystal structure and kinetic mechanism of aminoglycoside phosphotransferase-2''-IVa.

M.Toth, H.Frase, N.T.Antunes, C.A.Smith, S.B.Vakulenko.

ABSTRACT

Acquired resistance to aminoglycoside antibiotics primarily results from deactivation by three families of aminoglycoside-modifying enzymes. Here we report the kinetic mechanism and structure of the aminoglycoside phosphotransferase 2"-IVa (APH(2")-IVa), an enzyme responsible for resistance to aminoglycoside antibiotics in clinical enterococcal and staphylococcal isolates. The enzyme operates via a Bi Bi sequential mechanism in which the two substrates (ATP or GTP and an aminoglycoside) bind in a random manner. The APH(2")-IVa enzyme phosphorylates various 4,6-disubstituted aminoglycoside antibiotics with catalytic efficiencies (k(cat)/K(m)) of 1.5 x 10(3) to 1.2 x 10(6) (M(-1) s(-1)). The enzyme uses both ATP and GTP as the phosphate source, an extremely rare occurrence in the phosphotransferase and protein kinase enzymes. Based upon an analysis of the APH(2")-IVa structure, two overlapping binding templates specifically tuned for hydrogen bonding to either ATP or GTP have been identified and described. A detailed understanding of the structure and mechanism of the GTP-utilizing phosphotransferases is crucial for the development of either novel aminoglycosides or, more importantly, GTP-based enzyme inhibitors which would not be expected to interfere with crucial ATP-dependent enzymes.