Deciphering the molecular and functional basis of TMexCD1 : the plasmid-encoded efflux pump of resistance-nodulation-division superfamily

Horizontal gene transfer has been demonstrated to be an important driver for the emergency of multidrug-resistant pathogens. Recently, a transferable gene cluster tmexCD1-toprJ1 of the resistance-nodulation-division (RND) superfamily was identified in the plasmids of animal-derived Klebsiella pneumoniae strains, with a higher efflux capacity for various drugs than the Escherichia coli AcrAB-TolC homolog system. In this study, we focused on the differences in the inner membrane pump of these two systems and identified some key residues that contribute to the robust efflux activity of the TMexCD1 system. With the aid of homologous modeling and molecular docking, eight residues from the proximal binding pocket (PBP) and nine from the distal binding pocket (DBP) were selected and subjected to site-directed mutagenesis. Several of them, such as S134, I139, D181, and A290, were shown to be important for substrate binding in the DBP region, and all residues in PBP and DBP showed certain substrate preferences. Apart from the conservative switch loop (L613-623TMexD1) previously identified in the E. coli AcrB (EcAcrB), a relatively unconservative loop (L665-675TMexD1) at the bottom of PBP was proposed as a critical element for the robust activity of TMexD1, due to variations at sites E669, G670, N673, and S674 compared to EcAcrAB, and the significantly altered efflux activity due to their mutations. The conservation and flexibility of these key factors can contribute to the evolution of the RND efflux pumps and thus serve as potential targets for developing inhibitors to block the widespread of the TMexCD1 system.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:68

Enthalten in:

Antimicrobial agents and chemotherapy - 68(2024), 4 vom: 03. Apr., Seite e0167823

Sprache:

Englisch

Beteiligte Personen:

Shang, Yan [VerfasserIn]
Zhang, Ye [VerfasserIn]
Wang, Ruimin [VerfasserIn]
Peng, Yishu [VerfasserIn]
Ding, Bo [VerfasserIn]
Liu, Yuanxiang [VerfasserIn]
Li, Chongzhou [VerfasserIn]
Feng, Luhua [VerfasserIn]
Liu, Honglei [VerfasserIn]
Yang, Chunyu [VerfasserIn]
Tang, Yajie [VerfasserIn]

Links:

Volltext

Themen:

AcrB protein, E coli
Anti-Bacterial Agents
Escherichia coli Proteins
Journal Article
Loop 665–675
Multidrug Resistance-Associated Proteins
Multidrug resistance
RND efflux pump
Substrate-binding sites
TMexD1

Anmerkungen:

Date Completed 04.04.2024

Date Revised 05.04.2024

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1128/aac.01678-23

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM369672593