the Q cycle, has been proposed for the passage of electrons and protons through the complex. The net equation for the redox reactions of the Q cycle is

TLS Online TPP Program

#Id: 450

#Unit 2. Cellular Organization

All four core histones show a similar type of structure in which three a-helices are connected by two loops. This highly conserved structure is called the histone fold.

TLS Online TPP Program

#Id: 451

#Unit 2. Cellular Organization

Nucleosomes that contain linker H1 histones are referred to as chromatosomes.

TLS Online TPP Program

#Id: 452

#Unit 2. Cellular Organization

Lysine  in the histone tails are the most common targets of modification.

TLS Online TPP Program

#Id: 453

#Unit 2. Cellular Organization

Acetylation, methylation, ubiquitylation, and sumoylation all occur on the free epsilon amino group of lysine.

TLS Online TPP Program

#Id: 454

#Unit 2. Cellular Organization

Acetylation neutralizes the positive charge of lysine so disrupts DNA Histone interactions.

TLS Online TPP Program

#Id: 455

#Unit 2. Cellular Organization

lysine methylation retains the positive charge, and lysine can be mono-, di-, or trimethylated.