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Mourin M, Bhattacharjee A, Wai A, Hausner G, O'Neil J, Dibrov P. Pharmacophore-Based Screening & Modification of Amiloride Analogs for targeting the NhaP-type Cation-Proton Antiporter in Vibrio cholerae. Can J Microbiol 2021; 67:835-849. [PMID: 34224663 DOI: 10.1139/cjm-2021-0074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Structural and mutational analysis of Vc-NhaP2 identified a putative cation binding pocket formed by antiparallel extended regions of two transmembrane segments (TMSs V/XII) along with TMS VI. Molecular Dynamics (MD) simulations suggested that the flexibility of TMS-V/XII is crucial for the intra-molecular conformational events in Vc-NhaP2. In this study, we developed some putative Vc-NhaP2 inhibitors from Amiloride analogs (AAs). Molecular docking of the modified AAs revealed promising binding. The four selected drugs potentially interacted with functionally important amino acid residues located on the cytoplasmic side of TMS VI, the extended chain region of TMS V and TMS XII and the loop region between TMSs VIIII and IX. Molecular dynamics simulations revealed that binding of the selected drugs can potentially destabilize the Vc-NhaP2 and alters the flexibility of the functionally important TMS VI. The work presents the utility of in silico approaches for the rational identification of potential targets and drugs that could target NhaP2 cation proton antiporter to control Vibrio cholerae. The goal is to identify potential drugs that can be validated in future experiments.
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Affiliation(s)
- Muntahi Mourin
- University of Manitoba Faculty of Science, 124614, Microbiology, 66 chancellor drive, Winnipeg, Winnipeg, Manitoba, Canada, R3T 2N2;
| | - Arittra Bhattacharjee
- North South University, 54495, Biochemistry and Microbiology, Dhaka, Dhaka District, Bangladesh;
| | - Alvan Wai
- University of Manitoba, 8664, Winnipeg, Canada, R3T 2N2;
| | - Georg Hausner
- University of Manitoba, 8664, Buller Building 213, Buller Building 213, Manitoba, Winnipeg, Manitoba, Canada, R3T 2N2;
| | - Joe O'Neil
- University of Manitoba, 8664, Chemistry, Winnipeg, Manitoba, Canada;
| | - Pavel Dibrov
- University of Manitoba Faculty of Science, 124614, Microbiology, Winnipeg, Manitoba, Canada;
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Orriss GL, To V, Moya-Torres A, Seabrook G, O'Neil J, Stetefeld J. Solution structure of the cytoplasmic domain of NhaP2 a K +/H + antiporter from Vibrio cholera. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183225. [PMID: 32126231 DOI: 10.1016/j.bbamem.2020.183225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 02/08/2020] [Accepted: 02/10/2020] [Indexed: 11/24/2022]
Abstract
NhaP2 is a K+/H+ antiporter from Vibrio cholerae which consists of a transmembrane domain and a cytoplasmic domain of approximately 200 amino acids, both of which are required for cholera infectivity. Here we present the solution structure for a 165 amino acid minimal cytoplasmic domain (P2MIN) form of the protein. The structure reveals a compact N-terminal domain which resembles a Regulator of Conductance of K+ channels (RCK) domain connected to a more open C-terminal domain via a flexible 20 amino acid linker. NMR titration experiments showed that the protein binds ATP through its N-terminal domain, which was further supported by waterLOGSY and Saturation Transfer Difference NMR experiments. The two-domain organisation of the protein was confirmed by BIOSAXS, which also revealed that there are no detectable-ATP-induced conformational changes in the protein structure. Finally, in contrast to all known RCK domain structures solved to date, the current work shows that the protein is a monomer.
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Affiliation(s)
- George L Orriss
- University of Manitoba, Department of Chemistry, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada
| | - Vu To
- University of Manitoba, Department of Chemistry, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada
| | - Aniel Moya-Torres
- University of Manitoba, Department of Chemistry, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada
| | - Genevieve Seabrook
- The OCI/UHN High Field NMR Facility, MaRS Toronto Medical Discovery Tower, 101 College Street, Toronto, Ontario M5C 1L7, Canada
| | - Joe O'Neil
- University of Manitoba, Department of Chemistry, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada
| | - Jörg Stetefeld
- University of Manitoba, Department of Chemistry, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada.
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Physiological, Structural, and Functional Analysis of the Paralogous Cation-Proton Antiporters of NhaP Type from Vibrio cholerae. Int J Mol Sci 2019; 20:ijms20102572. [PMID: 31130620 PMCID: PMC6567090 DOI: 10.3390/ijms20102572] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 05/21/2019] [Accepted: 05/23/2019] [Indexed: 12/13/2022] Open
Abstract
The transmembrane K+/H+ antiporters of NhaP type of Vibrio cholerae (Vc-NhaP1, 2, and 3) are critical for maintenance of K+ homeostasis in the cytoplasm. The entire functional NhaP group is indispensable for the survival of V. cholerae at low pHs suggesting their possible role in the acid tolerance response (ATR) of V. cholerae. Our findings suggest that the Vc-NhaP123 group, and especially its major component, Vc-NhaP2, might be a promising target for the development of novel antimicrobials by narrowly targeting V. cholerae and other NhaP-expressing pathogens. On the basis of Vc-NhaP2 in silico structure modeling, Molecular Dynamics Simulations, and extensive mutagenesis studies, we suggest that the ion-motive module of Vc-NhaP2 is comprised of two functional regions: (i) a putative cation-binding pocket that is formed by antiparallel unfolded regions of two transmembrane segments (TMSs V/XII) crossing each other in the middle of the membrane, known as the NhaA fold; and (ii) a cluster of amino acids determining the ion selectivity.
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Mourin M, Wai A, O'Neil J, Schubiger CB, Häse CC, Hausner G, Dibrov P. A pathway leading to a cation-binding pocket determines the selectivity of the NhaP2 antiporter in Vibrio cholerae 1. Biochem Cell Biol 2018; 97:307-314. [PMID: 30011386 DOI: 10.1139/bcb-2018-0146] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The Vc-NhaP2 antiporter from Vibrio cholerae exchanges H+ for K+ or Na+ but not for the smaller Li+. The molecular basis of this unusual selectivity remains unknown. Phyre2 and Rosetta software were used to generate a structural model of the Vc-NhaP2. The obtained model suggested that a cluster of residues from different transmembrane segments (TMSs) forms a putative cation-binding pocket in the middle of the membrane: D133 and T132 from TMS V together with D162 and E157 of TMS VI. The model also suggested that L257, G258, and N259 from TMS IX together with T276, D273, Q280, and Y251 from TMS X as well as L289 and L342 from TMS XII form a transmembrane pathway for translocated ions with a built-in filter determining cation selectivity. Alanine-scanning mutagenesis of the identified residues verified the model by showing that structural modifications of the pathway resulted in altered cation selectivity and transport activity. In particular, L257A, G258A, Q280A, and Y251A variants gained Li+/H+ antiport capacity that was absent in the nonmutated antiporter. T276A, D273A, and L289A variants exclusively exchanged K+ for H+, while a L342A variant mediated Na+/H+ exchange only, thus maintaining strict alkali cation selectivity.
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Affiliation(s)
- M Mourin
- a Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - A Wai
- a Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - J O'Neil
- b Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - C B Schubiger
- c Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, USA
| | - C C Häse
- c Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, USA
| | - G Hausner
- a Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - P Dibrov
- a Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
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Functional Interaction between the N and C Termini of NhaD Antiporters from Halomonas sp. Strain Y2. J Bacteriol 2017; 199:JB.00302-17. [PMID: 28559301 DOI: 10.1128/jb.00302-17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 05/23/2017] [Indexed: 02/04/2023] Open
Abstract
Two NhaD-type antiporters, NhaD1 and NhaD2, from the halotolerant and alkaliphilic Halomonas sp. strain Y2, exhibit different physiological functions in regard to Na+ and Li+ resistance, although they share high sequence identity. In the present study, the truncation of an additional 4 C-terminal residues from NhaD2 or an exchange of 39 N-terminal residues between these proteins resulted in the complete loss of antiporter activity. Interestingly, combining 39 N-terminal residues and 7 C-terminal residues of NhaD2 (N39D2-C7) partially recovered the activity for Na+ and Li+ expulsion, as well as complementary growth following exposure to 300 mM Na+ and 100 mM Li+ stress. The recovered activity of chimera N39D2-C7 indicated that the N and C termini are structurally dependent on each other and function synergistically. Furthermore, fluorescence resonance energy transfer (FRET) analysis suggested that the N and C termini are relatively close in proximity which may account for their synergistic function in ion translocation. In the N-terminal region of N39D2-C7, the replacement of Glu38 with Pro abolished the recovered complementary and transport activities. In addition, this amino acid substitution in NhaD2 resulted in a drastically decreased complementation ability in Escherichia coli KNabc (level identical to that of NhaD1), as well as decreased activity and an altered pH profile.IMPORTANCE Limited information on NhaD antiporters supports speculation that these antiporters are important for resistance to high salinity and alkalinity. Moreover, only a few functional residues have been identified in NhaD antiporters, and there is limited literature on the molecular mechanisms of NhaD antiporter activity. The altered antiporter abilities of chimeras and mutants in this study implicate the functions of the N and C termini, especially Glu38, in pH regulation and ion translocation, and, most importantly, the essential roles of this negatively charged residue in maintaining the physiological function of NhaD2. These findings further our understanding of the molecular mechanism of NhaD antiporters for ion transport.
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Mourin M, Schubiger CB, Resch CT, Häse CC, Dibrov P. Physiology of the Vc-NhaP paralogous group of cation–proton antiporters in Vibrio cholerae. Mol Cell Biochem 2017; 428:87-99. [DOI: 10.1007/s11010-016-2919-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 12/21/2016] [Indexed: 10/20/2022]
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Aagesen AM, Schubiger CB, Hobson EC, Dibrov P, Häse CC. Effects of chromosomal deletion of the operon encoding the multiple resistance and pH-related antiporter in Vibrio cholerae. MICROBIOLOGY-SGM 2016; 162:2147-2158. [PMID: 27902431 DOI: 10.1099/mic.0.000384] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
To examine the possible physiological significance of Mrp, a multi-subunit cation/proton antiporter from Vibrio cholerae, a chromosomal deletion Δmrp of V. cholerae was constructed and characterized. The resulting mutant showed a consistent early growth defect in LB broth that became more evident at elevated pH of the growth medium and increasing Na+ or K+ loads. After 24 h incubation, these differences disappeared likely due to the concerted effort of other cation pumps in the mrp mutant. Phenotype MicroArray analyses revealed an unexpected systematic defect in nitrogen utilization in the Δmrp mutant that was complemented by using the mrpA'-F operon on an arabinose-inducible expression vector. Deletion of the mrp operon also led to hypermotility, observable on LB and M9 semi-solid agar. Surprisingly, Δmrp mutation resulted in wild-type biofilm formation in M9 despite a growth defect but the reverse was true in LB. Furthermore, the Δmrp strain exhibited higher susceptibility to amphiphilic anions. These pleiotropic phenotypes of the Δmrp mutant demonstrate how the chemiosmotic activity of Mrp contributes to the survival potential of V. cholerae despite the presence of an extended battery of cation/proton antiporters of varying ion selectivity and pH profile operating in the same membrane.
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Affiliation(s)
- Alisha M Aagesen
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, USA
| | - Carla B Schubiger
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, USA
| | - Eric C Hobson
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, USA
| | - Pavel Dibrov
- Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Claudia C Häse
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, USA
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Sodium-Proton (Na+/H+) Antiporters: Properties and Roles in Health and Disease. Met Ions Life Sci 2016; 16:391-458. [DOI: 10.1007/978-3-319-21756-7_12] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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