γ-Turn

Consists of 3 amino acids, generally termed as i, i + 1 and i + 2

H-bond is seen between i and i + 2 (First and Third residue)

The conformation of i + 1 is crucial and on the basis of this, they are classified into 2 groups

The dihedral angles of residue i + 1 are (70, -60) and (-70, 60) of the classical and inverse gamma turns

TLS Online TPP Program

#Id: 6323

#Unit 3. Fundamental Processes

Rho-dependent termination sites within a transcription unit are usually masked by translating ribosomes and therefore rho cannot act on downstream RNA polymerases

TLS Online TPP Program

#Id: 6324

#Unit 3. Fundamental Processes

Nonsense mutations release ribosomes within the RNA of a multigene operon, though, enabling rho to terminate transcription prematurely and prevent expression of distal genes in the transcription unit even though their open reading frames contained wild-type sequences.

TLS Online TPP Program

#Id: 6325

#Unit 3. Fundamental Processes

The b-subunit is obviously the determinant of rifampicin sensitivity or resistance.

TLS Online TPP Program

#Id: 758

#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).

TLS Online TPP Program

#Id: 759

#Unit 3. Fundamental Processes

Four Steps for bacterial transcription

1. Promoter search->closed promoter complex -> open promoter complex

2. Abortive transcription->Promoter Escape->Initiation from +1 TSS 

3. Elongation

4. Termination

TLS Online TPP Program

#Id: 760

#Unit 3. Fundamental Processes

Promoter search->closed promoter complex -> open promoter complex