Protein motors rotary motion

Motor proteins generate either linear or rotary motion (Table 3-2). Some motor proteins are components of macro-... 

The stator of rotary Fi motor is composed of six proteins. Three of them catalyze the hydrolysis of ATP, which drives the rotation of a shaft. The shaft of this Fi complex is glued to a proton turbine called Fq, which is located in the internal membrane of mitochondria. The whole FoFi-ATPase synthesizes ATP using the proton flow across the inner membrane. The Fi protein complex can function in reverse and serve as a motor performing mechanical work. These motors are modeled as stochastic systems with random jumps between the chemical states. If the rotation follows discrete steps and substeps, then the shaft has motions between well-defined orientations corresponding to the chemical states of the motor leading to a stochastic system based on discrete states. The result still will be the transition rates of the random jumps between the discrete states. These transition rates depend on the mass action law of chemical kinetics. 

Natural molecular motors (motor proteins) are intriguing, both as efficient products of evolution and as power sonrces for nanotechnology (7). Some representative rotary and linear motor proteins are subjects of this chapter. Not discussed here are a wide range of additional proteins in which linear motion is coupled with enzyme activity, or which perform physical work. Examples are RNA polymerase and DNA topoisomerase, respectively. 

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