Histone chaperone specificity in Rtt109 activation
Young-Jun Park1, Keely B Sudhoff, Andrew J Andrews
1Howard Hughes Medical Institute, Colorado State University, Fort Collins, Colorado 80523-1870, USA.
Nature Structural & Molecular Biology
|January 28, 2009
Summary
The histone acetyltransferase Rtt109 needs the Vps75 chaperone for histone modification. Vps75 specifically activates Rtt109, enabling efficient DNA replication and repair.
Area of Science:
- Biochemistry
- Molecular Biology
- Epigenetics
Background:
- Rtt109 is a histone acetyltransferase crucial for H3K56 acetylation.
- It functions in DNA replication and repair, requiring a histone chaperone.
- Rtt109 forms a complex with Vps75 in vivo.
Purpose of the Study:
- To investigate the roles of Rtt109 and Vps75 in histone acetylation.
- To elucidate the mechanism of Vps75 in activating Rtt109.
- To understand the structural and functional relationship between Vps75 and other chaperones.
Main Methods:
- Protein-histone binding affinity assays.
- Enzymatic activity assays for Rtt109.
- Crystal structure determination of Vps75.
- Comparison of Vps75 with Nap1.
Main Results:
- Both Rtt109 and Vps75 bind histones with high affinity.
- The Rtt109-Vps75 complex is catalytically efficient.
- Vps75's C-terminal acidic domain activates Rtt109 but is not essential for binding.
- Vps75 is a structural homolog of Nap1.
- Only Vps75, not Nap1, stimulates Rtt109 activity.
Conclusions:
- Vps75 plays a specific activating role in Rtt109-mediated H3K56 acetylation.
- Vps75's unique functional specificity is key to its role in DNA processes.
- Structural insights reveal Vps75 as a functional homolog of Nap1 with distinct regulatory capabilities.
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