The Ramachandran Principle is that alpha helices, beta strands, and

turns are the most likely conformations for a polypeptide chain to 

adopt, because most other conformations are impossible due to

steric collisions between atoms. 

TLS Online TPP Program

#Id: 2313

#Unit 3. Fundamental Processes

Splicing is an SN2 reaction that proceeds through a pentavalent phosphorous intermediate.

TLS Online TPP Program

#Id: 2314

#Unit 3. Fundamental Processes

There are three type of Splicing Machinery

 

TLS Online TPP Program

#Id: 2315

#Unit 3. Fundamental Processes

The group I and group II introns have the remarkable ability to excise themselves from an RNA. This is called auto-splicing, or self-splicing. 

Group I introns are more common than group II introns.

TLS Online TPP Program

#Id: 2316

#Unit 3. Fundamental Processes

Two transesterification reactions takes place for 2 exon -1 intron configuration. First transesterification is catalysed variably either by external G or branch point while second transesterification is always caused by exon 1 -3’OH.

 

TLS Online TPP Program

#Id: 2317

#Unit 3. Fundamental Processes

There are three type of Splicing signals 

Major U2-type or GU-AG introns

Minor U12-type or AU-AC introns

Minor U12-type with GU-AG introns (hybrid type)

TLS Online TPP Program

#Id: 2318

#Unit 3. Fundamental Processes

Major U2-type or GU-AG introns