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Molecular motors are natural (biological) or artificial molecular machines that are the essential agents of movement in living organisms. In general terms, a motor is a device that consumes energy in one form and converts it into motion or mechanical work ; for example, many protein -based molecular motors harness the chemical free energy ...
Synthetic molecular motors are molecular machines capable of continuous directional rotation under an energy input. [2] Although the term "molecular motor" has traditionally referred to a naturally occurring protein that induces motion (via protein dynamics), some groups also use the term when referring to non-biological, non-peptide synthetic motors.
In statistical mechanics, the Zimm–Bragg model is a helix-coil transition model that describes helix-coil transitions of macromolecules, usually polymer chains. Most models provide a reasonable approximation of the fractional helicity of a given polypeptide; the Zimm–Bragg model differs by incorporating the ease of propagation (self-replication) with respect to nucleation.
The helicity of a particle is positive (" right-handed") if the direction of its spin is the same as the direction of its motion and negative ("left-handed") if opposite. Helicity is conserved. [1] That is, the helicity commutes with the Hamiltonian, and thus, in the absence of external forces, is time-invariant. It is also rotationally ...
One scheme of nomenclature in based on envisioning the helicity defined by these groups. [11] Starting with the substituent of highest priority in the closest ring and moving along the shortest path to the substituent of highest priority in the other ring, the absolute configuration is assigned P or Δ for clockwise and M or Λ for ...
Many of these molecular motors are ubiquitous in both prokaryotic and eukaryotic cells, although some, such as those involved with cytoskeletal elements or chromatin, are unique to eukaryotes. The motor protein prestin, [14] expressed in mammalian cochlear outer hair cells, produces mechanical amplification in the cochlea. It is a direct ...
Unlike a molecular motor, any mechanical work done due to the motion in a switch is generally undone once the molecule returns to its original state unless it is part of a larger motor-like system. The image on the right shows a hydrazone -based switch that switches in response to pH changes.
In general terms, a motor is a device that consumes energy in one form and converts it into motion or mechanical work; for example, many protein-based molecular motors harness the chemical free energy released by the hydrolysis of ATP in order to perform mechanical work. [10]