“Structural Studies of Viral Macromolecular Complexes by Cryo-Electron Microscopy ”

_

Date and Time

4:00 PM – 5:30 PM Friday, October 3^th, 2025

Location

Onsite（CryoEM building）

Speakers: Yoko Fujita-Fujiharu

Postdoc
Max Planck Institute of Biochemistry
German,

Abstract

Understanding the architecture of viral macromolecular complexes is essential for elucidating the mechanisms of viral assembly and replication. While traditional structural biology often focuses on purified proteins in isolation, cryo-electron microscopy (cryo-EM) has the potential to analyze three-dimensional structures in more biologically relevant contexts.

In this talk, I will present some results from a study integrating multi-scale structural information of Ebola virus-like particles (VLPs). By combining in situ single-particle analysis and cryo-electron tomography, we resolved the structures of the viral matrix protein VP40 and the glycoprotein GP within intact VLPs. This multi-scale cryo-EM approach provides structural insights ranging from angstrom-level atomic detail to nanometer-scale organization, offering a more comprehensive understanding of viral assembly and function.

Click here to apply

“Enzymes: From Natural Diversity to Optimized Tools for Biomedical Applications – The Case of Antimicrobial Enzymes”

_

Date and Time

10:00 AM – 11:30 AM Wednesday, September 24^th, 2025

Location

Onsite（SBRC building）

Speakers: Dr. Claire STINES-CHAUMEIL

Associate Professor
Paul Pascal Research Centre
University of Bordeaux, FRANCE

Abstract

Enzymes are protein catalysts that can accelerate reaction rates by up to 1021-fold without altering the thermodynamic equilibrium. They are ubiquitous in biochemical transformations and often exhibit remarkable selectivity, a property rarely achieved by artificial catalysts. Enzymes have broad applications across various industries, including agri-food, textiles, PET degradation, drug synthesis, and medicine.
My research focuses on understanding the structure-function relationship of enzymes and elucidating their mechanisms, particularly those relevant to biomedical and biotechnological applications. I then optimize natural catalysts through genetic and protein engineering to enhance their suitability for specific uses, such as glucose biosensors, catheters, immunosensors, and disinfection.
In my talk, I will focus on microbicidal enzymes naturally involved in human innate immunity. I will present the strategies used to identify key enzymes and characterize their biochemical and physicochemical properties. These enzymes have been optimized to exhibit ideal antimicrobial properties for biomedical applications, such as combating nosocomial infections.

Click here to apply

“Time-resolved cryo-EM reveals mechanism of allosteric activation in isocitrate lyase 2”

_

Date and Time

4:00 PM – 5:30 PM Friday, September 26^th, 2025

Location

Hybrid (Zoom and KEK CryoEM building)

Speakers : Ghader Bashiri

Associate Professor
Laboratory of Microbial Biochemistry and Biotechnology
School of Biological Sciences, The University of Auckland

Abstract

Allostery is a fundamental regulatory mechanism underpinning many biochemical and physiological processes within cells. Allostery occurs when a binding event at one site on a protein affects binding at a remote functional site, thereby enabling precise control of enzymatic function. Isocitrate lyase 2 (ICL2) serves as a regulatory hub in the central metabolism of Mycobacterium tuberculosis, the bacterium that causes tuberculosis, where is modulates carbon flux in the central carbon metabolism.

Our crystal structures of Mtb-ICL2 demonstrate that binding of acetyl-CoA or propionyl-CoA at a site distant to the active site induces extensive conformational changes, leading to a ~100-fold increase in its enzymatic activity. Using time-resolved cryo-EM, we captured the trajectory of these structural transitions, from a time point as early as 150 ms through to the fully active state. Our data reveal the dynamic population shifts between protein conformations over time. Our findings provide unprecedented insights into the mechanisms underlying allosteric activation of Mtb-ICL2.

Click here to apply

“医学はアート？〜サイエンスに基づく臨床の思考プロセスに触れる〜”

_

Date and Time

2025年8月29日（金）　10:00

Location

オンサイト（構造生物棟会議室）

Speakers:

戒能 賢太

筑波大学　医学医療系　内分泌代謝・糖尿病内科

Abstract

構造生物学を含むあらゆる生物学研究の中でも、特に哺乳類を対象とした研究は、臨床応用を目的とすることが多いかと思います。研究成果に基づく診断ツールとしての検査法の開発や、新たな治療法の創出は比較的イメージしやすく、実際に日々新しい検査法や治療法が臨床の場で応用されており、医学は常に進歩を遂げていると言えます。しかし「検査」や「治療」といった選択肢は、患者さんが病院を訪れてから何らかの転帰に至るまでの過程全体の中ではあくまで一部分に過ぎず、実際、臨床医の思考の多くは適切な検査や治療を選択するまでのプロセスに費やされています。医学教育の礎を築いたウィリアム・オスラーは、そのプロセスを指して「医学とは、科学に基づく技術（アート）である」と表現しましたが、今回のセミナーでは、医学が対象とする領域の中でもそうした「アート的」側面に焦点を当て、その一端に触れていただければと思います。

Click here to apply