Structural and evolutionary analyses of the Plasmodium falciparum chloroquine resistance transporter.
Amino Acids
/ metabolism
Antimalarials
/ pharmacology
Chloroquine
/ pharmacology
Drug Resistance
/ genetics
Evolution, Molecular
Membrane Transport Proteins
/ chemistry
Mutation
Parasitic Sensitivity Tests
Phylogeny
Plasmodium falciparum
/ cytology
Protozoan Proteins
/ chemistry
Quinolines
/ pharmacology
Vacuoles
Journal
Scientific reports
ISSN: 2045-2322
Titre abrégé: Sci Rep
Pays: England
ID NLM: 101563288
Informations de publication
Date de publication:
16 03 2020
16 03 2020
Historique:
received:
12
08
2019
accepted:
24
02
2020
entrez:
18
3
2020
pubmed:
18
3
2020
medline:
15
12
2020
Statut:
epublish
Résumé
Mutations in the Plasmodium falciparum chloroquine resistance transporter (PfCRT) confer resistance to several antimalarial drugs such as chloroquine (CQ) or piperaquine (PPQ), a partner molecule in current artemisinin-based combination therapies. As a member of the Drug/Metabolite Transporter (DMT) superfamily, the vacuolar transporter PfCRT may translocate substrate molecule(s) across the membrane of the digestive vacuole (DV), a lysosome-like organelle. However, the physiological substrate(s), the transport mechanism and the functional regions of PfCRT remain to be fully characterized. Here, we hypothesized that identification of evolutionary conserved sites in a tertiary structural context could help locate putative functional regions of PfCRT. Hence, site-specific substitution rates were estimated over Plasmodium evolution at each amino acid sites, and the PfCRT tertiary structure was predicted in both inward-facing (open-to-vacuole) and occluded states through homology modeling using DMT template structures sharing <15% sequence identity with PfCRT. We found that the vacuolar-half and membrane-spanning domain (and especially the transmembrane helix 9) of PfCRT were more conserved, supporting that its physiological substrate is expelled out of the parasite DV. In the PfCRT occluded state, some evolutionary conserved sites, including positions related to drug resistance mutations, participate in a putative binding pocket located at the core of the PfCRT membrane-spanning domain. Through structural comparison with experimentally-characterized DMT transporters, we identified several conserved PfCRT amino acid sites located in this pocket as robust candidates for mediating substrate transport. Finally, in silico mutagenesis revealed that drug resistance mutations caused drastic changes in the electrostatic potential of the transporter vacuolar entry and pocket, facilitating the escape of protonated CQ and PPQ from the parasite DV.
Identifiants
pubmed: 32179795
doi: 10.1038/s41598-020-61181-1
pii: 10.1038/s41598-020-61181-1
pmc: PMC7076037
doi:
Substances chimiques
Amino Acids
0
Antimalarials
0
Membrane Transport Proteins
0
PfCRT protein, Plasmodium falciparum
0
Protozoan Proteins
0
Quinolines
0
Chloroquine
886U3H6UFF
piperaquine
A0HV2Q956Y
Types de publication
Journal Article
Research Support, Non-U.S. Gov't
Langues
eng
Sous-ensembles de citation
IM
Pagination
4842Références
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