生化学と分析生化学

概要

Tubulin Conformation and Anaesthetic Interaction - An Experimental Study

Pushpa Sahni, Bhanupriya, Shreya and Jaya

The current endeavour of neuroscience and philosophy is to discover the code of consciousness or rather how the material brain produces our in Material sense of awareness. Some scientists believe that consciousness is something distinct from the physical brain and body, as consciousness continues to exist even when the brain is not functioning. But from a scientific viewpoint, consciousness is a function of the brain. Since the brain is a material entity, consciousness is subject to the study of science. The human brain is a complex mass of tissue endowed with extraordinary capabilities. Microtubules turn out to be a common target of neurotransmitter action and play a significant role in learning and memory. Memory and consciousness are interrelated, thus, microtubules could be the link between these two phenomena. Microtubules are cylindrical hexagonal lattice polymers of the protein tubulin, comprising 15% of total brain protein. Microtubules regulate synapses and are suggested to process information via interactive bit-like states of tubulin. Microtubules are very dynamic polymers whose assembly and disassembly is determined by whether their heterodimer tubulin subunits are in a straight or curved conformation. Curvature is introduced by bending at the interfaces between monomers. This is because GTP hydrolysis promotes bends in protofilaments. However, while GDPbound protofilaments are still associated together as a microtubule or 2-D sheet, the contacts between neighbouring subunits constrain them to remain in a straight form. The resulting tension is proposed to store conformational energy that is released during depolymerisation. Also, the mechanism by which anaesthetics prevent consciousness remains largely unknown because the mechanism by which brain physiology produces consciousness is unexplained. Tubulins have other smaller non-polar regions that contain pi electron-rich indole rings separated by only about 2 nm. Penrose- Hameroff Orchestrated Objective Reduction (Orch-OR) Theory proposes that these electrons are close enough to become quantum entangled. They suppose that quantum-superposed states develop in tubulins, remain coherent and recruit more superposed tubulins until a mass-time-energy threshold, related to quantum gravity, is reached called as the 'bing' moment. This paper characterizes the conformation of tubulin in presence of anesthetics.