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4 results on '"Shah-Mohammadi N"'

2. Solution structure analysis of the periplasmic region of bacterial flagellar motor stators by small angle X-ray scattering

Author

Liew, CW, Hynson, RM, Ganuelas, LA, Shah-Mohammadi, N, Duff, AP, Kojima, S, Homma, M, and Lee, LK

Subjects
Models, Molecular, Biochemistry & Molecular Biology, Sequence Homology, Amino Acid, Molecular Motor Proteins, Salmonella enterica, Recombinant Proteins, Solutions, Bacterial Proteins, X-Ray Diffraction, Protein Domains, Flagella, Scattering, Small Angle, Amino Acid Sequence, Protein Structure, Quaternary, Vibrio alginolyticus, Bacterial Outer Membrane Proteins
Abstract

© 2017 Elsevier Inc. The bacterial flagellar motor drives the rotation of helical flagellar filaments to propel bacteria through viscous media. It consists of a dynamic population of mechanosensitive stators that are embedded in the inner membrane and activate in response to external load. This entails assembly around the rotor, anchoring to the peptidoglycan layer to counteract torque from the rotor and opening of a cation channel to facilitate an influx of cations, which is converted into mechanical rotation. Stator complexes are comprised of four copies of an integral membrane A subunit and two copies of a B subunit. Each B subunit includes a C-terminal OmpA-like peptidoglycan-binding (PGB) domain. This is thought to be linked to a single N-terminal transmembrane helix by a long unstructured peptide, which allows the PGB domain to bind to the peptidoglycan layer during stator anchoring. The high-resolution crystal structures of flagellar motor PGB domains from Salmonella enterica (MotBC2) and Vibrio alginolyticus (PomBC5) have previously been elucidated. Here, we use small-angle X-ray scattering (SAXS). We show that unlike MotBC2, the dimeric conformation of the PomBC5 in solution differs to its crystal structure, and explore the functional relevance by characterising gain-of-function mutants as well as wild-type constructs of various lengths. These provide new insight into the conformational diversity of flagellar motor PGB domains and experimental verification of their overall topology.

Published
2017

3. Solution structure analysis of the periplasmic region of bacterial flagellar motor stators by small angle X-ray scattering

Author

Liew, CW, Hynson, RM, Ganuelas, LA, Shah-Mohammadi, N, Duff, AP, Kojima, S, Homma, M, Lee, LK, Liew, CW, Hynson, RM, Ganuelas, LA, Shah-Mohammadi, N, Duff, AP, Kojima, S, Homma, M, and Lee, LK

Abstract

© 2017 Elsevier Inc. The bacterial flagellar motor drives the rotation of helical flagellar filaments to propel bacteria through viscous media. It consists of a dynamic population of mechanosensitive stators that are embedded in the inner membrane and activate in response to external load. This entails assembly around the rotor, anchoring to the peptidoglycan layer to counteract torque from the rotor and opening of a cation channel to facilitate an influx of cations, which is converted into mechanical rotation. Stator complexes are comprised of four copies of an integral membrane A subunit and two copies of a B subunit. Each B subunit includes a C-terminal OmpA-like peptidoglycan-binding (PGB) domain. This is thought to be linked to a single N-terminal transmembrane helix by a long unstructured peptide, which allows the PGB domain to bind to the peptidoglycan layer during stator anchoring. The high-resolution crystal structures of flagellar motor PGB domains from Salmonella enterica (MotBC2) and Vibrio alginolyticus (PomBC5) have previously been elucidated. Here, we use small-angle X-ray scattering (SAXS). We show that unlike MotBC2, the dimeric conformation of the PomBC5 in solution differs to its crystal structure, and explore the functional relevance by characterising gain-of-function mutants as well as wild-type constructs of various lengths. These provide new insight into the conformational diversity of flagellar motor PGB domains and experimental verification of their overall topology.

Published
2018

4. Transcriptome profiling analysis of the seagrass, Zostera muelleri under copper stress.

Author

Shah Mohammadi N, Buapet P, Pernice M, Signal B, Kahlke T, Hardke L, and Ralph PJ

Subjects
Aquatic Organisms, Copper administration & dosage, Dose-Response Relationship, Drug, Gene Expression Profiling, Gene Expression Regulation, Plant drug effects, Plant Leaves drug effects, Plant Leaves genetics, Water Pollutants, Chemical administration & dosage, Copper toxicity, Water Pollutants, Chemical toxicity, Zosteraceae drug effects, Zosteraceae genetics
Abstract

Copper (Cu) in an essential trace metal but it can also contaminate coastal waters at high concentrations mainly from agricultural run-off and mining activities which are detrimental to marine organisms including seagrasses. The molecular mechanisms driving Cu toxicity in seagrasses are not clearly understood yet. Here, we investigated the molecular responses of the Australian seagrass, Z. muelleri at the whole transcriptomic level after 7 days of exposure to 250 μg Cu L -1 and 500 μg Cu L -1 . The leaf-specific whole transcriptome results showed a concentration-dependent disturbance in chloroplast function, regulatory stress responses and defense mechanisms. This study provided new insights into the responses of seagrasses to trace metal stress and reports possible candidate genes which can be considered as biomarkers to improve conservation and management of seagrass meadows., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Published
2019
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