Article
Biology
Hideyuki Matsunami, Young-Ho Yoon, Katsumi Imada, Keiichi Namba, Fadel A. Samatey
Summary: The crystal structure of the flagellar hook cap from Salmonella enterica was determined by X-ray crystallography, revealing insights into a putative hook assembly mechanism. The pentameric structure of the hook cap, divided into a stalk region and a petal region, plays a key role in facilitating the assembly of the hook. The N-terminal domains of the hook cap are essential for its hook-capping function, and a plausible hook assembly mechanism promoted by the hook cap is proposed based on the structure.
COMMUNICATIONS BIOLOGY
(2021)
Article
Physics, Multidisciplinary
Xinwen Zhang, Chi Zhang, Rongjing Zhang, Junhua Yuan
Summary: The bacterial hook is a universal joint that connects the flagellar motor and the filament, playing a crucial role in bacterial swimming. The mechanical properties of the hook are essential for the normal functioning of the flagellum. In this study, the bending stiffness of the hook was measured under clockwise (CW) and counterclockwise (CCW) rotation, revealing that the hook stiffens under CW rotation, enabling multiflagellated bacteria to perform robust run-and-tumble swimming.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Fluids & Plasmas
Zonghao Zou, Wilson Lough, Saverio Spagnolie
Summary: The study investigates the importance and impact of bacterial flagella on microorganism locomotion using a simplified model. It shows that the paths of cell bodies driven by a single flagellum are typically helical in Stokes flow, and identifies a critical ratio for a supercritical Hopf bifurcation in flagellar orientation, affecting the cell's trajectory significantly. The research provides consistent predictions for the trajectory's helical amplitude using relevant parameters.
PHYSICAL REVIEW FLUIDS
(2021)
Article
Chemistry, Multidisciplinary
William M. Dawson, Freddie J. O. Martin, Guto G. Rhys, Kathryn L. Shelley, R. Leo Brady, Derek N. Woolfson
Summary: The rational design of linear peptides that assemble in water is challenging, as unique target structures must be encoded and alternative states avoided. Weak non-covalent forces that stabilize and discriminate between states present a challenge. However, progress has been made in rational de novo design for alpha-helical coiled-coil assemblies.
Article
Biochemistry & Molecular Biology
Anna-Maria Tsirigoni, Melis Goktas, Zeynep Atris, Angelo Valleriani, Ana Vila Verde, Kerstin G. Blank
Summary: Coiled coils are crucial for biogenic materials and their mechanical response. A transition from alpha-helices to beta-sheets occurs in CC-based materials under force, which depends on the pulling speed and CC length. This transition is observed in simulations and experiments, highlighting the importance of both factors.
MACROMOLECULAR BIOSCIENCE
(2023)
Article
Biology
Piotr Kolesinski, Kuei-Chen Wang, Yujiro Hirose, Victor Nizet, Partho Ghosh
Summary: This study revealed the specific binding mechanism between the Streptococcus pyogenes M protein and the human antimicrobial peptide LL-37, providing important insights into the drug resistance of streptococcus.
Article
Physics, Multidisciplinary
Seungsoo Hahn
Summary: Alpha-helix and alpha-helical coiled coils are important structural motifs in biology. This study investigates their vibrational characteristics by systematically changing their structural parameters. Additionally, the changes in their infrared spectrum according to structural variations are explored.
JOURNAL OF THE KOREAN PHYSICAL SOCIETY
(2022)
Article
Physics, Fluids & Plasmas
Takuya Goto, Katsuji Ichiguchi, Hitoshi Tamura, Junichi Miyazawa, Shinsuke Satake, Hiroyuki Yamaguchi, Nagato Yanagi
Summary: The study found that by changing the pitch modulation of the helical coils, the core plasma performance of the LHD-type helical fusion reactor can be significantly improved, leading to an expansion of the reachable operation region and an increase in the expected fusion gain.
PLASMA AND FUSION RESEARCH
(2021)