CAP–cAMP increases the rate of formation of the closed promoter complex, CAP–cAMP provides CPC for conversion to the open promoter complex. 

Thus, the net effect of CAP–cAMP is to increase the rate of open promoter complex formation.

TLS Online TPP Program

#Id: 1523

#Unit 2. Cellular Organization

Primary building block of intermediate filaments is a dimer held together through the rod domains, which associate as a coiled coil.

TLS Online TPP Program

#Id: 1524

#Unit 2. Cellular Organization

Two dimers 

Tetramers

Protofilaments (Tetramers are assembled end to end)

Protofibril (Four protofilaments)

10-nm filament (Four protofibrils associate side

TLS Online TPP Program

#Id: 1525

#Unit 2. Cellular Organization

TLS Online TPP Program

#Id: 1526

#Unit 2. Cellular Organization

Microtubules can be stabilized by side-binding microtubule associated proteins (MAPs).

TLS Online TPP Program

#Id: 1527

#Unit 2. Cellular Organization

The short (∼20 amino acid) C-terminal tails of both α- and β-tubulin that protrude from the microtubule are enriched in glutamic and aspartic acids, the surface of the microtubule possesses a net negative charge.

TLS Online TPP Program

#Id: 1528

#Unit 2. Cellular Organization

Many MAPs are positively charged and bind to microtubles through electrostatic interactions.