TBP causes the minor groove to be widened to an almost flat conformation; it also bends the DNA by an angle of 80. The interaction between TBP and DNA involves only a limited number of hydrogen bonds between the protein and the edges of the base pairs in the minor groove.  Instead, much of the specificity is imposed by two pairs of phenylalanine side chains that intercalate between the base pairs at either end of the recognition sequence and drive the strong bend in the DNA.

TLS Online TPP Program

#Id: 3997

#Unit 2. Cellular Organization

In a natural closed DNA that is negatively supercoiled, the intercalation of ethidium bromide first removes the negative supercoils and then introduces positive supercoils.

TLS Online TPP Program

#Id: 4559

#Unit 8. Inheritance Biology

Gene Interaction with Epistasis

The effect of gene interaction is that one gene masks (hides) the effect of another gene at a different locus.

TLS Online TPP Program

#Id: 5700

#Unit 7. System Physiology – Animal

The anterior pituitary secretes six peptide hormones: 

TSH, FSH, LH, GH, prolactin, & ACTH

TLS Online TPP Program

#Id: 9800

#Unit 6. System Physiology – Plant

Proportion of phytochrome in the Pfr form after saturating irradiation by red light is only about 85%. 

TLS Online TPP Program

#Id: 9029

#Unit 6. System Physiology – Plant

Under ‘‘light conditions,’’ reduced thioredoxin cleaves the disulfide bonds of CP12 and phosphoribulokinase. 

The reduction of phosphoribulokinase and CP12 separates the

components of the ternary complex releasing the active phosphoribulokinase and the active A4B4-glyceraldehyde 3-phosphate dehydrogenase.