Related Experiment Video
Updated: Jun 4, 2026
11:09
Characterizing the Composition of Molecular Motors on Moving Axonal Cargo Using "Cargo Mapping" Analysis
Published on: October 30, 2014
Maximum directionality and systematic classification of molecular motors
1Department of Physics, NUS Graduate School for Integrative Sciences and Engineering, and Centre for Computational Science & Engineering, National University of Singapore, 2 Science Drive 3, Singapore 117542. ArtemEfremov@yandex.ru phywangz@nus.edu.sg
Physical Chemistry Chemical Physics : PCCP
|February 8, 2011
Summary
This study introduces directionality as a new metric for evaluating molecular motor performance. It provides a framework for comparing and classifying various motors, guiding artificial motor development and revealing biomotor evolution.
Area of Science:
- Biophysics
- Nanotechnology
- Molecular Machines
Background:
- Track-walking molecular motors are essential for intracellular transport in living cells.
- Artificial molecular motors are actively researched for engineered systems.
- Molecular motors convert energy to achieve directed motion from random thermal motion.
Purpose of the Study:
- To derive a general formulation for maximum molecular motor performance.
- To introduce and define 'directionality' as a novel performance metric.
- To establish a quantitative framework for comparing diverse molecular motors.
Main Methods:
- Developed a general representation for track-walking motors.
- Derived a formulation for maximum motor performance based on directionality.
- Analyzed various experimentally demonstrated and theoretically proposed motors.
Main Results:
- Directionality serves as a robust indicator of a motor's rectification mechanism and design.
- Distinct upper limits of directionality were identified for different motor types.
- A quantitative comparison and classification of motors based on mechanistic advancement were achieved.
Conclusions:
- Maximum directionality offers a conceptual framework for understanding and comparing molecular motors.
- The findings provide guidelines for the development of artificial molecular motors.
- The study reveals insights into the evolutionary strategies of biological motors.
Related Concept Videos
01:32Microtubule Associated Motor Proteins
Eukaryotic cells have different motor proteins for transporting various cargo within the cell. These motor proteins differ based on the filament they associate with, the direction they move within the cell, and the type of cargo they transport. Motor proteins that associate with microtubules are known as microtubule-associated motor proteins. There are two families of microtubule-associated motor proteins —Kinesins and Dyneins. Both these proteins assist in the transport of cellular cargos...
01:43The Movement of Organelles and Vesicles
In eukaryotic cells, cytoskeletal filaments such as actin, microtubules, and intermediate filaments form a mesh-like cytoskeletal network. These filaments serve as tracks for transporting cellular cargo. Specialized motor proteins use the chemical energy stored in adenosine triphosphate (ATP) for this transport. During interphase, microtubules are polarized, with the plus-end towards the cell periphery and the minus-end towards the cell center. Two microtubule-associated motor proteins,...
01:15Overview of Myosin Structure and Function
Myosins are a family of molecular motor proteins, first identified in the skeletal muscles, where they are responsible for muscle contraction. Along with their role in muscle contraction, these proteins also play a role in the intracellular transport of molecules and vesicles. There are twenty-four classes of myosins based on their domain sequence and organization. Of the twenty-four, six classes (Myosin I, Myosin II, Myosin V, Myosin VI, Myosin VII, and Myosin X) have been well characterized.
01:39Anaphase A and B
Microtubules form through the end-to-end polymerization of tubulin heterodimers. Kinetochore microtubules originate from the spindle poles, and their plus-ends connect with the kinetochores on sister-chromatids. Ndc80 protein complexes, present on the kinetochore, form low-affinity links with the plus end of these kinetochore microtubules.
Plus-end depolymerization releases tubulin heterodimers from the terminal region of the microtubule. As tubulin subunits are lost, the Ndc80 complexes detach...
Plus-end depolymerization releases tubulin heterodimers from the terminal region of the microtubule. As tubulin subunits are lost, the Ndc80 complexes detach...
00:46Motor Units
A motor unit consists of two main components: a single efferent motor neuron (i.e., a neuron that carries impulses away from the central nervous system) and all of the muscle fibers it innervates. The motor neuron may innervate multiple muscle fibers, which are single cells, but only one motor neuron innervates a single muscle fiber.
01:13Motor Units
The motor unit is a fundamental component of the neuromuscular system and plays a crucial role in coordinating muscle contractions. It consists of a somatic motor neuron, which connects and controls multiple skeletal muscle fibers, forming a single functional segment. The axon of the motor neuron branches out and establishes synaptic connections known as neuromuscular junctions with individual muscle fibers within the motor unit.
Motor units come in different sizes, with smaller units...
Motor units come in different sizes, with smaller units...