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The structural basis of the cross-bridge cycle
DECORATED ACTIN was the first em reconstruction Moore, Huxley, and DeRosier 1970 J. Mol Biol.
Reconstruction by filtered least squares
Projection every 1° (181 projections) Number of observational equations is 161 x 181=29141 Order of normal matrix Problem should be well determined
Case 2. Projection every 3°, not enough data to invert the normal matrix. How much data is there? To determine the rank of a positive (semi) definite matrix we determine its eigenvalue spectrum
Decorated actin at 13Å resolving power calculated by filtered least squares
Electron cryo-microscopy (of decorated actin) shows how strong binding of myosin to actin releases nucleotide Holmes, Angert, Kull, Jahn, Schroeder (2003) Nature 425,
Four sub-domain refinement
The cross-bridge cycle As revealed by crystallography
Geeves, M.A. & Holmes, K.C. (2005) The molecular mechanism of muscle contraction Adv Protein Chem 71,
Lymn & Taylor, 1971
The myosin motor domain must move the lever arm from pre- to post- power stroke. It must bind to actin strongly or weakly Both functions are controlled by ATP binding and hydrolysis
Crystallography on the motor domain (particularly Dictyostelium Myosin 2) shows two conformations of myosin: lever UP and lever DOWN
Diskussionsthemen Nennen Sie die Hauptthesen, über die Sie sprechen werden.
Thema 1 Details über das Thema Argumente und Beispiele Warum ist das Thema für Ihr Publikum von Bedeutung?
Fischer et al (2005) PNAS
Weak and Strong Binding
Coureux, P. D.Wells, A. L.Menetrey, J.Yengo, C. M.Morris, C. A.Sweeney, H. L.Houdusse, A. (2003) A structural state of the myosin V motor without bound nucleotide Nature
Upper/lower 50K fitted
Time table Hugh Huxley Introduction. 6 mins. X-ray interference experiments 28 mins. on whole muscles. Yale Goldman Structural dynamics of individual 28.
Molecular motors Biological molecular machines that are the essential agents of movement in living organisms wiki.
Outline: The Lymn-Taylor cycle PCA method (theory & applications) Individual involvement coefficient (theory & applications) Summary Future work.
Basic Electron Microscopy Arthur Rowe The Knowledge Base at a Simple Level.
IN CLASS NOTES = STEPS OF A MUSCLE CONTRACTION. STEP 1 Calcium ions present Ca+ binds to troponin which makes tropomyosin move out of way for myosin head.
Docking Molecular Structures into EM. Introduction Detailed models of proteins are required in order to elucidate the structure-function relationship.
Skeletal Muscle Contraction Sliding Filament Model actin myosin Fig
Muscles Muscle Structure A very high resolution E.M reveals that each myofibril is made up of parallel filaments. There are 2 kinds of filament.
Excitation-contraction coupling Sliding filament mechanism independent studies by Huxley and Huxley (no relation) in 1954.
Ron Rock University of Chicago The Role of the Proximal Tail in the Large Steps of Myosin VI.
Myosin Myosin is a protein molecule found in the thick filaments. Myosin is a protein molecule found in the thick filaments.
Sliding Filament Theory How do muscles work…... Muscle Cell Structure n Muscles are broken into smaller muscle fibers n muscle fibers are broken into.
Physiology of Skeletal Muscle Contraction. The Muscle Action Potential ( AP ) The Muscle Action Potential ( AP ) Muscle RMP = -90 mV ( same as in nerves.
RLC ELC Myopathy Loop Actin-Binding Loop Helix- Loop- Helix Motor Domain Lever-Arm 50 kD Cleft Active Site Crystal Structure of Myosin S1 Lever Arm.
Lecture 2 Outline: Brief overview of a long history Sarcomere structure and function Myosin Regulation of contraction Paper: A large protein required for.
Hair cells, actin bundles, and unconventional myosins.
The Use of the Energy in ATP for Muscle Contractions Nitya Anand Melissa Donaldson Leigh McDonald Chris Smyre.
Molecular Basis of Muscle Contraction Standard 9 h. Students know the cellular and molecular basis of muscle ocntraction,including the roles of actin,
Module 632 Lecture 8 JCS Mechanism of Muscle contraction.
Motor Proteins - Introduction Part 2 Biochemistry 4000 Dr. Ute Kothe.
Motor mechanisms. Keywords (reading p ) Bundle, fiber, myofibril, sarcomere Z-line, thick filament, thin filament Actin, myosin, sliding filament.
Contraction of skeletal muscle. Learning objectives What evidence supports the sliding filament mechanism of muscle contraction? How does the sliding.
Molecular Basis of Muscle Contraction Mercedita Macalintal, MD, DPPS.
Muscle Contractions Sliding Filament Theory. Goal: I will be able to explain the Sliding Filament Theory.
The Steps of Muscle Contraction: The Sliding Filament Theory.
Muscle contraction. Students participating in the presentation: 1- naif aljabri yousif alessa faris abalkheel Ali.
The Molecular Motor Myosin Jonathan P. Davis, Ph.D. Assistant Professor Office/Lab Phone Department of Physiology and.
Chapter 5.3: Actin, Myosin, and Molecular Motors CHEM 7784 Biochemistry Professor Bensley.
Sliding Filament Mechanism Ch notes. Sliding Filament Mechanism Describes the cause and mechanism of muscle contraction Myosin heads attach to and.
Biophysics Master Course, Fall 2002 Some of the physics cells have to deal with: Random walks, diffusion and Brownian motion.
CONTRACTION OF SKELETLAL MUSCLE: SLIDING FILAMENT THEORY PROPOSED BY: H.E. HUXLEY & J. HANSEN.
Sliding Filament Model of Muscle Contraction Larry M. Frolich, Ph.D. April 15, 2010 HOOK Muscle is only biological cell/tissue that can cause rapid, large-scale.
Myosin is a motor that runs along (or tugs at) actin. Actin-based movement of vesicles Chromosome migration Myosin-driven cell shape changes Muscle contraction.
What is evidence that EC coupling works as described?
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Destruction of Acetylcholine ACh bound to ACh receptors is quickly destroyed.
Cytoskeltal Motors. Network of long protein strands located in the cytosol not surrounded by membranes Consist of microtubules and microfilaments Microfilaments.
Molecular Cell Biology Myosin Cooper. Diagram of a Sarcomere.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Neuromuscular Junction Figure 9.7 (a-c)
The Contraction Cycle Process Diagrams Step-by-Step Copyright © 2007 by John Wiley & Sons, Inc.
Depolarization Initially, this is a local electrical event called end plate potential Initially, this is a local electrical event called end plate potential.
MUSCLE CONTRACTION. Microscopic Anatomy of Skeletal Muscle Sarcomere Contractile unit of a muscle fiber Figure 6.3b.
* Acetylcholine * Actin * ATP * Ca+ ions * Myosin heads * Na+/K+ ions * Troponin * Tropomyosin * Sarcoplasmic reticulum * Z-line.
Movement Topic Assessment Statements 11.2 U1 Bones and exoskeletons provide anchorage for muscles and act as levers U2 Synovial joints allow.
Motor Proteins - Introduction Part 1 Biochemistry 4000 Dr. Ute Kothe.
09_10 Sliding filament theory Slide number: 1 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Tropomyosin.
Anatomy & Physiology Park Tudor School Skeletal Muscle Activity: Contraction Chapter 6 Part 2A.
Action Potential Depolarization –Initially, this is a local electrical event called end plate potential –Later, it ignites an action potential that spreads.
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