StructuralBiology

Key Research Areas

• Membrane protein function
• Cyro-Electron Microscopy

Research Overview

Dr Stewart’s research aims to understand how membrane proteins function. His lab uses a complementary spectrum of structural, biochemical and cellular methods, especially cryo-electron microscopy, to probe the inner workings of a range of molecular targets.

There are 2 key projects underway in the Structural Biology Laboratory;

1. ATP synthase function

ATP synthases are ubiquitous protein complexes that couple ATP synthesis/hydrolysis with proton translocation via a rotary catalytic mechanism. Our lab is using cryo-Electron Microscopy to generate high resolution information on ATP synthase under a range of conditions, including those inhibited by small molecules such as antibiotics.

2. Transporter function

The SLC22s are family are membrane proteins that facilitate the movement of endogenous and exogenous compounds across cell membranes. Because they can transport a vast number of pharmacological agents, members of the SLC22 family are referred to as “drug transporters” and have key implications for drug disposition. We are generating high resolution information on a range of SLC22 transporters bound to a range to small molecules, to understand the molecular basis of transport and inhibition of clinically relevant compounds.

Funding

• NHMRC Investigator Grant 2023-2027
• NHMRC Career Development Fellowship 2019-2022
• NHMRC Project Grant 2018-2020 (CIA)
• NHMRC Project Grant 2018-2020 (CIB)
• NHMRC Early Career Fellowship - Peter Doherty Biomedical 2015-2018

1. Zeng YC*, Sobti M, Quinn A, Smith NJ, Brown SHJ, Vandenberg JI, Ryan RM, O’Mara ML & Stewart AG* (Oct, 2023) ‘Structural Basis of Promiscuous Substrate Transport by Organic Cation Transporter 1 ’, Nature Communications; https://doi.org/10.1038/s41467...
2. Rouet R⁺, Henry JL⁺, Johansen MD⁺, Sobti M⁺, Balachandran H, Langley DB, Walker GJ, Lenthall H, Jackson J, Ubiparipovic S, Mazigi O, Schofield P, Burnett DL, Brown SHJ, Martinello M, Hudson B, Gilroy N, Post JJ, Kelleher A, Jäck H, Goodnow CC, Turville CG, Rawlinson WD, Bull RA*, Stewart AG*, Hansbro PM* & Christ D* (Feb, 2023) ‘Broadly neutralizing SARS-CoV-2 antibodies through epitope-based selection from convalescent patients’, Nature Communications; https://doi.org/10.1038/s41467...
3. Sobti M, Zeng YC, Walshe JL, Brown SHJ, Ishmukhametov R & Stewart AG* (Jan, 2023) 'Changes within the central stalk of E. coli F₁F_o ATP synthase observed after addition of ATP', Communications Biology; https://doi.org/10.1038/s42003...
4. Sobti M, Ueno H, Noji H* & Stewart AG* (Aug, 2021) ‘The six steps of the complete F₁-ATPase rotary catalytic cycle', Nature Communications; https://doi.org/10.1038/s41467...
5. Chen I⁺, Pant S⁺, Wu Q⁺, Cater RJ, Sobti M, Vandenberg RJ, Stewart AG, Tajkhorshid E*, Font J* & Ryan RM* (Feb, 2021) 'Glutamate transporters have a chloride channel with two hydrophobic gates', Nature; https://doi.org/10.1038/s41586...
6. Sobti M, Walshe JL, Wu D, Ishmukhametov R, Zeng YC, Robinson CV, Berry RM & Stewart AG* (May, 2020) 'Cryo-EM structures provide insight into how E. coli F₁F_o ATP synthase accommodates symmetry mismatch', Nature Communications; https://doi.org/10.1038/s41467...
7. Sobti M, Ishmukhametov R, Bouwer JC, Ayer A, Suarna C, Smith NJ, Christie M, Stocker R, Duncan TM & Stewart AG* (Mar, 2019), 'Cryo-EM reveals distinct conformations of E. coli ATP synthase on exposure to ATP', eLife; https://doi.org/10.7554/eLife....
8. Chorev DS, Baker LA, Wu D, Beilsten- Edmands V, Rouse SL, Zeev-Ben-Mordehai T, Jiko C, Samsudin F, Gerle C, Khalid S, Stewart AG, Matthews SJ, Grünewald K & Robinson CV* (Nov, 2018), 'Protein assemblies ejected directly from native membranes yield complexes for mass spectrometry', Science; https://doi.org/10.1126/scienc...
9. Sobti M, Smits C, Wong ASW, Ishmukhametov R, Stock D, Sandin S & Stewart AG* (Dec, 2016) 'Cryo-EM structures of the autoinhibited E. coli ATP synthase in three rotational states', eLife; https://doi.org/10.7554/eLife....
10. Chaston JJ, Smits C, Aragao D, Ahsan B, Sandin S, Molugu SK, Molugu SK, Bernal RA, Stock D* & Stewart AG* (Mar 2016), 'Structural and functional insights into the evolution and stress adaptation of type II chaperonins', Structure; https://doi.org/10.1016/j.str....