Molecular characterization of lpxACD and pmrA/B two-component regulatory system in the colistin resistance Acinetobacter baumannii clinical isolates

Ghahraman, Mohammad Reza Kandehkar; Hosseini-Nave, Hossein; Azizi, Omid; Shakibaie, Mohammad Reza; Mollaie, Hamid Reza; Shakibaie, Samane

doi:10.1016/j.genrep.2020.100952

Cited by 9 publications

(14 citation statements)

References 40 publications

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“…In our previous study, a colistin-resistant A. baumannii was isolated from intensive care unit of a teaching hospital in Kerman, Iran. The isolate was confirmed phenotypically and genetically by biochemical and PCR-sequencing tests as described before [16] . The MIC of colistin-resistant isolate was determined by microbroth dilution test as described by CLSI 2019 (reviewed in [16] ).…”

Section: Bacterial Identification and Molecular Typingmentioning

confidence: 99%

“…The isolate was confirmed phenotypically and genetically by biochemical and PCR-sequencing tests as described before [16] . The MIC of colistin-resistant isolate was determined by microbroth dilution test as described by CLSI 2019 (reviewed in [16] ). In order to find out the sequence type of the isolate, we performed MLST as per Oxford's scheme [16] .…”

Section: Bacterial Identification and Molecular Typingmentioning

confidence: 99%

“…The MIC of colistin-resistant isolate was determined by microbroth dilution test as described by CLSI 2019 (reviewed in [16] ). In order to find out the sequence type of the isolate, we performed MLST as per Oxford's scheme [16] .…”

Section: Bacterial Identification and Molecular Typingmentioning

confidence: 99%

“…Both strands of pmrA/B genes were sequenced by the ABI 373 Prism DNA sequencer (Applied Biosystems 373/3730XL model, Bioneer, Korea) [16] . The nucleotide and amino acid sequences were then compared with known sequences deposited in the NCBI website (https://www.ncbi.nlm.nih.gov) using the BLAST program (www.ncbi.nlm.nih.gov/blast).…”

Section: Dna Sequencing and Gene Annotationmentioning

confidence: 99%

“…Full-length PmrA/B DNA sequences obtained from our previous sequencing [16] were deposited in the GenBank database (NCBI) under accession numbers MN787072 (pmrA) and MN787073 (pmrB). The PmrA/B amino acid sequences were also deposited in the NCBI under accession numbers QIC34671 (PmrA) and QIC34672 for (PmrB).…”

Section: Nucleotide and Protein Sequence Accession Numbersmentioning

confidence: 99%

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Stereochemical Trajectories of a Two-Component Regulatory System PmrA/B in a Colistin-Resistant Acinetobacter baumannii Clinical Isolate

Kandehkar-Ghahraman

Hosseini-Nave

Azizi

et al. 2021

ibj

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Background: There is limited information on the 3D prediction and modeling of the colistin resistance-associated proteins PmrA/B TCS in Acinetobacter baumannii. We aimed to evaluate the stereochemical structure and domain characterization of PmrA/B in an A. baumannii isolate resistant to high-level colistin, using bioinformatics tools. Methods: The species of the isolate and its susceptibility to colistin were confirmed by PCR-sequencing and MIC assay, respectively. For 3D prediction of the PmrA/B, we used 16 template models with the highest quality (evalue <1 × 10−50). Results: Prediction of the PmrA structure revealed a monomeric non-redundant protein consisting of 28 α-helices and 22 β-sheets. The PmrA DNA-binding motif displayed three antiparallel α-helices, followed by three β-sheets, and was bond to the major groove of DNA by intermolecular van der Waals bonds through amino acids Lys, Asp, His, and Arg, respectively. Superimposition of the deduced PmrA 3D structure with the closely related PmrA protein model (GenBank no. WP_071210493.1) revealed no distortion in conformation, due to Glu→Lys substitution at position 218. Similarly, the PmrB protein structure displayed 24 α-helices and 13 β-sheets. In our case, His251 acted as a phosphate receptor in the HisKA domain. The amino acid substitutions were mainly observed at the putative N-terminus region of the protein. Furthermore, two substitutions (Lys21→Ser and Ser28→Arg) in the transmembrane domain were detected. Conclusion: The DNA-binding motif of PmrA is highly conserved, though the N-terminal fragment of PmrB showed a high rate of base substitutions. This research provides valuable insights into the mechanism of colistin resistance in A. baumannii.

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Section: Bacterial Identification and Molecular Typingmentioning

confidence: 99%