15:15-16:15

Conformational analysis of receptor protein for biomimetic nanobio interface

Our interest is to understand the information processing mechanism in the brain, and to develop devices that can communicate with the brain using receptor proteins. The key idea behind this research is the fusion of a receptor conformation/function and a synaptic connection/function. We are studying the conformational changes induced by neurotransmitter reception to enable us to understand the relationship between conformational change and function.

In this talk, I will introduce our study of (1) the conformational analysis of purified/reconstituted receptor protein by AFM, (2) the in vivo measurement of neural activity using a PEDOT-PSS modified electrode, (3) a bio-mimetic synapse using a lipid bilayer with a nano-cavity, and (4) the differentiation and electro-activity of neurostem cells. Some studies were carried out in collaboration with foreign universities, such as the University of Oxford.

Speaker

Prof. Keiichi Torimitsu , Basic Research Laboratories, Nippon Telegraph and Telephone Corporation (NTT), Japan

Chair

Dr. Masakazu Aono, MANA Director-General, NIMS

16:15-17:15

Atomic Force Microscopy Imaging of Receptor Proteins

Nanoscale measurement techniques have many potential applications in biology and medicine, ranging from molecular diagnostics and early stage detection of disease to targeted drug delivery. These techniques have the ability to image and manipulate individual molecules and to measure molecular interactions in real time with sub-molecular resolution.

In this talk I will describe recent progress in using atomic force microscopy (AFM) to measure membrane proteins. In many respects these molecules are the basic information processing devices in biology: they are responsible for sensory signal input and transduction, and they control and regulate numerous biological processes. They include:

- ion channels, that allow specific ions to permeate the cell membrane and thereby control the trans-membrane voltage;

- receptors, that respond to small molecules, such as hormones and amino acids, thereby transmitting signals to cells and modulating their behaviour.

Their immense importance is indicated by the fact that up to 30% of all genes code for membrane proteins. Furthermore, they represent 60% all drug targets.

I will present AFM measurements of:

(a) the prototypical potassium ion channel KcsA, and pH-dependent changes related to gating,

(b) neuroreceptors such as AMPA receptors, which are involved in the processes of memory and learning, and

(c) photoreceptors involved in the process of energy transduction, e.g. bacteriorhodopsin (bR), which is a light-driven proton pump.

While recent advances in x-ray crystallography and nuclear magnetic resonance have greatly improved our understanding of membrane protein structure, the new AFM techniques permit real-time imaging of the protein function with few-Å resolution in a physiological environment.

* This work was carried out in collaboration with: T. Ando, S. Antoranz Contera, N. Kasai, C. Ramanujan, K. Sumitomo, K. Torimitsu, T. Uchihashi, K. Voitchovsky and H. Yamashita

Speaker

Prof. John Ryan, Clarendon Laboratory, University of Oxford, UK

Chair

Dr. Noboru Miura, Managing Director, ICYS, NIMS