Final answer:
The Che proteins responsible for flagella rotation direction are CheY, CheZ, CheA, and CheB. These proteins exhibit motions such as the movement of α-helices and β-pleated sheets during catalysis. Additionally, proteins like MreB and FtsZ might be part of a primitive prokaryotic cytoskeleton.
Step-by-step explanation:
The four Che proteins involved in flagella rotation direction are CheY, CheZ, CheA, and CheB. When CheY is phosphorylated, it interacts with the flagellar motor to cause a change in the direction of rotation. CheA is a histidine kinase that phosphorylates CheY, CheB, and itself in response to signals from chemoreceptors. CheZ acts to dephosphorylate CheY, effectively resetting the system. CheB, which is also modulated by CheA through phosphorylation, serves a role in the adaptation process by demethylating chemoreceptors.
In terms of structural changes, it is known that proteins can exhibit motion as they catalyze reactions, including movements of loops, α-helices, and β-pleated sheets. However, determining which specific structures move in the Che proteins requires an analysis of the individual protein's tertiary structure and is beyond the direct scope of this question.
The FtsZ gene encodes a protein homologous to tubulin, and along with flagellin, the MreB and FtsZ proteins might be involved in forming a primitive prokaryotic cytoskeleton contributing to cell structure and motility. Also, some bacteria have internal membranes that enable functions akin to organelles, such as photosynthesis and chemolithotrophy.