In NPLC order of elution of analytes is such that the least polar is eluted first and the most polar last.

TLS Online TPP Program

#Id: 2296

#Unit 3. Fundamental Processes

Three general models were proposedfor abortive transcription.

TLS Online TPP Program

#Id: 2297

#Unit 3. Fundamental Processes

Two bases in the non-template strand of the –10 element (A11 and T7) flip out from their base-stacking interactions and instead insert into pockets within the s protein where they make more favorable interactions

TLS Online TPP Program

#Id: 2298

#Unit 3. Fundamental Processes

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: 2299

#Unit 3. Fundamental Processes

By 1969 SDS-PAGE of RNA polymerase from E. coli had shown several subunits

1.2 very large subunits are b (150 kD) and b’ (160 kD)

2. Sigma (s) at 70 kD

3. Alpha (a) at 40 kD – 2 copies present in holoenzyme

4. Omega (w) at 10 kD 

TLS Online TPP Program

#Id: 2300

#Unit 3. Fundamental Processes

The overall reaction rate for the bacterial RNA polymerase can be as fast as 40–50 nucleotides/ second at 37°C for most transcripts

TLS Online TPP Program

#Id: 2301

#Unit 3. Fundamental Processes

The overall reaction rate for the bacterial RNA polymerase can be as fast as 40–50 nucleotides/ second at 37°C for most transcripts; this is about the same as the rate of translation (15 amino acids/sec), but much slower than the rate of DNA replication (800 bp/sec).