MICR3240 - Motility and Chemotaxis

Clockwise

tumble/ change direction 

Counter clockwise

run

FliM

is the motor switch,
controlling the direction
of flagellar rotation

bacteria use temporal sensing

comparing conc of chemical now compared to just a moment ago

CheW works with

cytoplasmic receptor

CheA works with

CheW

cheY that’s phosp. then

dissociates and can connect with the flagellar to change direction of it

CheZ

dephos. CheY

CheR

resets receptor to sense higher amounts of conc. by covalently and chemically modifying cytoplasmic tail of methyl accepting receptor 

What does adding a ch3 group do to the cytoplasmic tail of the receptor

normally tails diverges due to glutamic acid the ch3 group neutralizes the charge allowing the tail to come back together

CheA uses ATP to

autophosphorylate 

CheZ dephosphorylates causing 

CheY to terminate the response 

Attractant binds MCP

CheA is inactivated, CheZ dephoshorylates CheY, rotor turn CCW

CheB when phosphorylated

removes CH3 groups from the MCP thus
restoring the sensitivity of the MCP to the
normal level

CheA, CheW, CheY, and CheR mutants are

smooth-swimming

CheZ and CheB mutants are

tumbly