Zinc Finger Motif

Zinc atom stabilizes the structure/fold by coordination bonds

Each motif contains about 30-50 amino acids

Contains regular patterns of Cys / His, which coordinate with Zinc atom

Contains one helix and two small anti-parallel beta sheets in each finger

Zinc holds helix and beta-sheets together

Helix binds to DNA

TLS Online TPP Program

#Id: 6664

#Unit 3. Fundamental Processes

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

TLS Online TPP Program

#Id: 6665

#Unit 3. Fundamental Processes

There are three type of Splicing Machinery

TLS Online TPP Program

#Id: 6666

#Unit 3. Fundamental Processes

TLS Online TPP Program

#Id: 6667

#Unit 3. Fundamental Processes

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

Group I introns are more common than group II introns.

TLS Online TPP Program

#Id: 6668

#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: 6669

#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)