The transition from the closed to the open complex involves structural changes in the enzyme and the opening of the DNA double helix to reveal the template and nontemplate strands. This “melting” occurs between positions –11 and +2, with respect to the transcription start site.

TLS Online TPP Program

#Id: 1548

#Unit 2. Cellular Organization

Nocodazole and colchicine

TLS Online TPP Program

#Id: 1549

#Unit 2. Cellular Organization

Two main families of motor proteins mediate transport along microtubules:

Kinesins 

Dyneins

TLS Online TPP Program

#Id: 1550

#Unit 2. Cellular Organization

Kinesin-1 powers anterograde transport of vesicles down axons toward the (+) ends of microtubules.

TLS Online TPP Program

#Id: 1551

#Unit 2. Cellular Organization

Kinesin-1  (similar to myosin II)

Head domain at the N-terminus of the heavy chain  

Stalk domain forms a long coiled-coil

Tail domain at C-terminus that attaches to cargo

TLS Online TPP Program

#Id: 1552

#Unit 2. Cellular Organization

Kinesin-5 forms tetramers, assembled in a bipolar configuration to interact with two antiparallel microtubules and move toward the (+) ends.

TLS Online TPP Program

#Id: 1553

#Unit 2. Cellular Organization

Kinesin-14 is a C-terminal kinesin & travel toward the microtubule minus end.