Both the pi helix and the 310 helix occur rarely and usually only at the ends of a helices or as single-tum helices. They are not energetically favorable, since the backbone atoms are too tightly packed in the 310 helix and so loosely packed in the n helix that there is a hole through the middle. 

Only in the a helix are the backbone atoms properly packed to provide a stable structure.

TLS Online TPP Program

#Id: 6221

#Unit 12. Applied Biology

Retroviral Vectors Retroviruses have RNA genomes that are used as templates for reverse transcriptase to synthesize a DNA copy that can be inserted into the host cell genome.

TLS Online TPP Program

#Id: 6222

#Unit 12. Applied Biology

The genomes of all retroviruses contain the three genes gag, pol and env.

TLS Online TPP Program

#Id: 6223

#Unit 12. Applied Biology

TLS Online TPP Program

#Id: 6224

#Unit 12. Applied Biology

TLS Online TPP Program

#Id: 6225

#Unit 12. Applied Biology

TLS Online TPP Program

#Id: 6226

#Unit 12. Applied Biology

The genomes of all retroviruses contain the three genes gag, pol and env.

For sustainable expression of a trangene in the successive generation of a cell line in culture, the ideal gene transfer can be obtained using 

 lentiviral vector 

adenoviral vector 

 plasmid DNA containing the transgene 

only transgenic DNA