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POSTER
PRESENTATIONS
 
 
 
 
 
 
 
 
 

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Poster presentation 
37 
PROTEIN SEQUENCES ANALYSIS OF THE MAIN MDR PUMP 
ACRAB-TOLC FROM ESCHERICHIA COLI:
ANTIBACTERIAL 
ACTION OF SUBSTANCES OF PLANT ORIGIN 
Marina V. Karakozova, 
Vasilisa N. Raldugina
,
Pavel A. Nazarov, 
 
Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State 
University, Moscow, Russia 
Multidrug-resistance (MDR) pumps are the cornerstone of protecting bacteria from 
antibiotics. MDR pumps form the basis of non-specific protection of bacteria and 
belong to six families of MDR pumps. One of the best studied MDR pumps is the E. 
coli AcrAB-TolC pump. The study of pump sequences is an important task in 
understanding the processes of formation of new clinical isolates-superbugs, since 
resistance due to efflux occupies an important place in the total number of resistant 
bacteria arising as a result of antibiotic therapy. It is believed that the genes encoding 
MDR pumps are variable and belong to the so-called “luxury” genes, i.e., they are 
designed to adapt bacteria to changing environmental conditions. In this work, we 
analyzed all known sequences of TolC, AcrA, and AcrB proteins from 
E. coli
strains, 
and based on the results obtained, we found important patterns for understanding the 
formation of resistance in the bacterial population. TolC, AcrA, and AcrB protein 
sequences for 
E. coli
strains were downloaded from the NCBI database in genbank and 
fasta formats using the biopython package and the Etrez.Esearch and Entrez.Efetch 
functions. In this work, all currently existing sequences of the AcrAB-TolC proteins in 
the NCBI database were analyzed: TolC (8383 sequences), AcrA (5715 sequences), and 
AcrB (3561 sequences). The sequences were aligned with each other using BLASTp 
with the creation of an individual database. For further work with the data, the numpy 
and pandas packages were used. Analysis of laboratory strains showed that the 
sequences of a large number of laboratory strains used (K-12 and B) are conserved and 
do not detect any mutation in the amino acid sequences. This allows us to state that for 
each protein there are certain consensus sequences that do not change. Analysis of all 
sequences showed that there are several consensus sequences in the 
E. coli
population 
and for each protein and there are many point mutations around these consensus 
sequences. However, consensus sequences predominate in the population, and this 
explains the fact that several decades of laboratory cultivation did not affect laboratory 
strains of E. coli. This normalizes the use of different laboratory strains in relation to at 
least the AcrAB-TolC pump in various studies. The conservatism of amino acid 
sequences of the pumps resembles the conservatism of the “housekeeping” genes, 
which indicates the great importance of these genes for bacteria, despite the fact that 
these genes are formally classified as nonessential genes. In this work, we used an 
approach to analyze the effect of plant substances based on quinones and terpenes on 
their ability to penetrate into bacterial cells. 
This research was funded by Russian Science Foundation (RSF) grant 22-15-00099. 

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Poster presentation 
38