Rodgers 2-21 Flashcards
HCP
Histone core particle- the octamer unit that forms the nucleosome histone. Made of H2A, H2B, H3, H4
Which amino acids are essential for forming salt bridges with the Phosphate backbone of the DNA
Arginine and lysine
What is the functional domain of HCP’s?
histone-fold domain (helix-turn-helix-turn-helix motif)
Which of the HCP’s are first to form at the DNA loop?
The H3-H4 tetramer
In what order do the HAP’s congregate?
H3-H4 tetramer, H2A-H2B dimers
Four functions of histone chaperones
Storage, assembly, disassembly, losening for translation
FACT
H3-H4 chaperone, many important roles
Histone reservoirs
An important means for repopulating the daughter chromosomes with histones after replication
How many planes of symmetry in a nucleosome Unit?
2
Which histone tetramer interacts with the middle and ends of the DNA of the nucleosome?
H3-H4
Where are the most symmetrical histones found?
at the centromere- because of the palindromic alpha-satellite sequences - easiest to crystallize
How do nucleosome complexes optimize DNA-protein interactions
The grooves are narrower and more negative on the inside of the DNA loop where positive basic residues bond to the DNA (and form salt bridges with the backbone)
where and how do the sugar clamp motifs interact with the DNA
they operate in the narrowed minor groove by making hydrophobic interactions in the DNA sugars (with proline and leucine)
How do the helices of histone protein provide specificity (in addition to the affinity created by interacting with the backbone?)
They interact with water molecules that bridge the gap between the backbone and the protein (specific because of the sequence-determined conformation of the DNA)
What determines the amount of slide, shift, roll et cetera?
Sequence of base pairs (base-step parameters)
