Mechanical work contractile machines

Contractile Machines That Perform Mechanical Work by Pulling... 

Such shape changes cause contractile protein-based machines to perform mechanical work. 

The contractile protein machines of Life, however, accomplish more than the mechanical work of pumping iron or of rotation. 

As shown in the hexagonal array in Figure 5.22, five different energy inputs can perform mechanical work by the consilient mechanism. The set of elastic-contractile model proteins capable of direct utilization of hydrophobic association for contraction are called protein-based molecular machines of the first kind. These are enumerated below with brief consideration of the reversibility of these machines. 

The concept of two distinct but interlinked mechanical processes, expanded here as the coupling of hydrophobic and elastic consilient mechanisms, entered the public domain in the publication of Urry and Parker. Experimental results on elastic-contractile model proteins forged the concept, and the work of Urry and Parker extended the concept to contraction in biology. Unexpected in our examination of the relevance of this perspective to biology was to find the first clear demonstration of the concept in biology in a protein-based machine of the electron transport chain as a transmembrane protein of the inner mitochondrial membrane. Unimaginable was the occurrence of the coupled forces precisely at the nexus at which electron transfer couples to proton pumping. 

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