Description
This book compares the mechanisms of mechano-chemical enzymes, cytoskeleton-dependent motors and molecular machines acting on DNA and other cell constituents. Most of them utilize the energy of nucleotide triphosphate hydrolysis to amplify kinetic events to give rise to relatively large conformational changes. However, the mechanistic paths of these machines are adapted to their specific cellular requirements. Molecular machines shape the cell, move intracellular cargo, sort their compartments and localize organelles within the cell, and defects in these sophisticated molecules may cause cellular defects and medical disabilities. Understanding the principles may lead to pharmacological and therapeutic applications.
The book comprises three main parts:
- Part I introduces the necessary background in physical chemistry and molecular biophysics. The relevance of time scales of protein dynamics, chemical reactions, and diffusion are discussed. As transitions between intermediate states are relevant, a thorough introduction to kinetic concepts is given.
- Part II presents experimental approaches. At the most basal level, enzymatic ensemble assays are sufficient, but advanced methods use pre-steady state kinetics, or single-molecule experiments involving fluorescence resonance transfer, or laser trap assays giving insight to force-independent transitions.
- Part III discusses selected examples, specifically actin-dependent motors (Myosin II and V), microtubule-dependent motors and severing AAA ATPases (kinesin, dynein, spastin/katanin), DNA motors (RecBCD, SpoEIII, phi29) and large GTPases (atlastin).
Section I: Physical and Chemical Background.- Chapter 1: Physics at the Molecular Level.- Chapter 2: Kinetics Fundamentals.- Section II Experimental Strategies.- Chapter 3: Classical Kinetic Models.- Chapter 4: Peculiarities of Single-molecule Assays.- Chapter 5: Mathematics and Computer Approaches.- Section III Selected Examples.- Chapter 6: DNA Motors: RecBCD, FtsK/SpoIIIE, Phage Packing Motor.- Chapter 7: Cytoskeletal Motors: Myosin II and V, Kinesin, Dynein, Intraflagellar Transport.- Chapter 8: Hexameric ATPases: F1Fo ATPase, ClpX, Microtubule-severing AAA ATPases.- Conclusion and Future Prospects.
Günther Woehlke studied biology and microbiology. After his studies in Bonn, Marburg and Munich, and postdoctoral studies at the UCSF, he has worked at the Institute for Cell Biology at the Ludwig-Maximilians-Universität, and the Department of Biophysics at the Technische Universität München. In his research, G. Woehlke has focussed on biological machines. Initially interested in the conversion of chemical fuel into membrane potentials, he has turned into research on mechano-chemical energy conversion, specifically on microtubule-associated mechano-enzymes. He has used various biophysical and kinetic methods to understand structure-function relationships.
Moreover, he has been interested in biomedical implications of mechano-enzymes. Kinesins and enzymes controlling the dynamics of microtubules have been found to cause neurodegenerative disorders in patients with hereditary genetic alterations. G. Woehlke has studied the molecular basis of the pathogenesis. Apart from primary scientific publications, he has contributed chapters on the cytoskeleton and the extracellular matrix for a medical textbook, and on biophysics for high school educators. His teaching activities are ranging from molecular cell biology, physical chemistry and physics, to biomedical topics.
