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In Vivo Cross-Linking MS Reveals Conservation in OmpA Linkage to Different Classes of β-Lactamase Enzymes

Xuefei Zhong1, Xia Wu1, Devin K Schweppe1

  • 1Department of Genome Sciences University of Washington School of Medicine 850 Republican Street, Brotman Building, Room 154 Seattle , Washington 98109 , United States.

Journal of the American Society for Mass Spectrometry
|February 8, 2020
PubMed

Insights

Outer membrane protein A (OmpA) interacts with different beta-lactamase enzymes in Acinetobacter baumannii. These interactions suggest conserved binding sites, with OmpA anchoring beta-lactamases in the periplasmic space.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Structural Biology

Background:

  • Acinetobacter baumannii is a multi-drug-resistant pathogen.
  • Beta-lactamase enzymes confer resistance to beta-lactam antibiotics.
  • Outer membrane protein A (OmpA) is a key outer membrane protein in Gram-negative bacteria.

Purpose of the Study:

  • To investigate the molecular interactions between OmpA and two distinct classes of beta-lactamase enzymes.
  • To identify the specific binding sites of beta-lactamases on OmpA.
  • To understand the functional significance of these interactions in antibiotic resistance.

Main Methods:

  • In vivo chemical cross-linking coupled with mass spectrometry (XL-MS) was employed.
  • A multi-drug-resistant strain of Acinetobacter baumannii AB5075 was used.
  • Analysis focused on Class A (blaGES-11) and Class D (Oxa23) beta-lactamases.

Main Results:

  • Both blaGES-11 and Oxa23 cross-linked to similar lysine sites on the periplasmic domain of OmpA.
  • Despite low sequence homology between the beta-lactamases, their interaction sites with OmpA were conserved.
  • The C-terminus domain of OmpA was identified as crucial for anchoring beta-lactamases.

Conclusions:

  • The interacting surfaces between beta-lactamases and OmpA are evolutionarily conserved.
  • OmpA plays a significant role in stabilizing various beta-lactamase enzymes within the periplasmic space.
  • This conserved interaction mechanism may represent a potential target for novel antimicrobial strategies against Acinetobacter baumannii.
Keywords:
AB5075OmpAOxa23blaGES-11in vivo cross-linking

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