Structural and Biochemical Characterization of Aminoglycoside Nucleotidyltransferase(6)-Ib From Campylobacter fetus subsp. fetus.
Nalam, P., Cook, P.D., Smith, B.A.(2025) Proteins 93: 413-419
- PubMed: 39246239
- DOI: https://doi.org/10.1002/prot.26745
- Primary Citation of Related Structures:
8VXB - PubMed Abstract:
Aminoglycoside antibiotics have played a critical role in the treatment of both Gram-negative and Gram-positive bacterial infections. However, antibiotic resistance has severely compromised the efficacy of aminoglycosides. A leading cause of aminoglycoside resistance is mediated by bacterial enzymes that inactivate these drugs via chemical modification. Aminoglycoside nucleotidyltransferase-6 (ANT(6)) enzymes inactivate streptomycin by transferring an adenyl group from ATP to position 6 on the antibiotic. Despite the clinical significance of this activity, ANT(6) enzymes remain relatively uncharacterized. Here, we report the first high resolution x-ray crystallographic structure of ANT(6)-Ib from Campylobacter fetus subsp. fetus bound with streptomycin. Structural modeling and gel filtration chromatography experiments suggest that the enzyme exists as a dimer in which both subunits contribute to the active site. Moreover, superposition of the ANT(6)-Ib structure with the structurally related enzyme lincosamide nucleotidyltransferase B (LinB) permitted the identification of a putative nucleotide binding site. These data also suggest that residues D44 and D46 coordinate essential divalent metal ions and D102 functions as the catalytic base.
Organizational Affiliation:
Department of Chemistry, Grand Valley State University, Allendale, Michigan, USA.