Characterization of the multidrug efflux transporter styMdtMfrom Salmonella enterica serovar Typhi
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Characterization of the multidrug efflux transporter styMdtMfrom Salmonella enterica serovar Typhi. / Shaheen, Aqsa; Ismat, Fouzia; Iqbal, Mazhar; Haque, Abdul; Ul-Haq, Zaheer; Mirza, Osman; De Zorzi, Rita; Walz, Thomas; Rahman, Moazur.
In: Proteins: Structure, Function, and Bioinformatics, Vol. 89, No. 9, 2021, p. 1193-1204.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Characterization of the multidrug efflux transporter styMdtMfrom Salmonella enterica serovar Typhi
AU - Shaheen, Aqsa
AU - Ismat, Fouzia
AU - Iqbal, Mazhar
AU - Haque, Abdul
AU - Ul-Haq, Zaheer
AU - Mirza, Osman
AU - De Zorzi, Rita
AU - Walz, Thomas
AU - Rahman, Moazur
N1 - © 2021 Wiley Periodicals LLC.
PY - 2021
Y1 - 2021
N2 - Salmonellae are foodborne pathogens and the major cause of gastroenteritis in humans. Salmonellae express multidrug efflux transporters that play a key role in their drug resistance, which is becoming an increasing problem for therapeutic intervention. Despite their biomedical importance, the mechanisms underlying substrate transport by multidrug efflux transporters remain poorly understood. Here, we describe the first characterization of a multidrug transporter belonging to the major facilitator superfamily from the genus Salmonella. We show that several clinical Salmonella Typhi (S. Typhi) isolates constitutively express the styMdtM (STY4874) gene, which encodes a known multidrug-resistance (MDR) transporter. Guided by the structure of the Escherichia coli (E. coli) homolog, we studied two residues critical for substrate transport, Asp25 and Arg111. Mutation of Asp25 to glutamate did not affect the transport function of styMdtM, whereas mutation to alanine reduced its transport activity, suggesting that a negative charge at this position is critical for substrate translocation across the membrane. Substrate-affinity measurements by intrinsic fluorescence spectroscopy showed that the Asp25Ala mutant retained its capacity to bind substrate, albeit at a lower level. Mutation of Arg111 to alanine resulted in a decrease in secondary structure content of the transporter, and mutation to lysine completely destabilized the structure of the transporter. A homology model of styMdtM suggests that Arg111 is important for stabilizing the transmembrane domain by mediating necessary interactions between neighboring helices. Together, our studies provide new structural and mechanistic insights into the Salmonella MDR transporter styMdtM.
AB - Salmonellae are foodborne pathogens and the major cause of gastroenteritis in humans. Salmonellae express multidrug efflux transporters that play a key role in their drug resistance, which is becoming an increasing problem for therapeutic intervention. Despite their biomedical importance, the mechanisms underlying substrate transport by multidrug efflux transporters remain poorly understood. Here, we describe the first characterization of a multidrug transporter belonging to the major facilitator superfamily from the genus Salmonella. We show that several clinical Salmonella Typhi (S. Typhi) isolates constitutively express the styMdtM (STY4874) gene, which encodes a known multidrug-resistance (MDR) transporter. Guided by the structure of the Escherichia coli (E. coli) homolog, we studied two residues critical for substrate transport, Asp25 and Arg111. Mutation of Asp25 to glutamate did not affect the transport function of styMdtM, whereas mutation to alanine reduced its transport activity, suggesting that a negative charge at this position is critical for substrate translocation across the membrane. Substrate-affinity measurements by intrinsic fluorescence spectroscopy showed that the Asp25Ala mutant retained its capacity to bind substrate, albeit at a lower level. Mutation of Arg111 to alanine resulted in a decrease in secondary structure content of the transporter, and mutation to lysine completely destabilized the structure of the transporter. A homology model of styMdtM suggests that Arg111 is important for stabilizing the transmembrane domain by mediating necessary interactions between neighboring helices. Together, our studies provide new structural and mechanistic insights into the Salmonella MDR transporter styMdtM.
U2 - 10.1002/prot.26141
DO - 10.1002/prot.26141
M3 - Journal article
C2 - 33983672
VL - 89
SP - 1193
EP - 1204
JO - Proteins: Structure, Function, and Bioinformatics
JF - Proteins: Structure, Function, and Bioinformatics
SN - 0887-3585
IS - 9
ER -
ID: 272115253