Biophysical characterization and structural studies of two E1A-interacting proteins: The pRB tumor suppressor and the PCAF coactivor.

Format:

Book

Thesis/Dissertation

Author/Creator:

Egan, Adrienne Clements.

Contributor:

University of Pennsylvania.

Language:

English

Subjects (All):

Biophysics.

Biochemistry.

0487.

0786.

Local Subjects:

0487.

0786.

Physical Description:

147 pages

Contained In:

Dissertation Abstracts International 62-02B.

System Details:

Mode of access: World Wide Web.

text file

Summary:

This two-part biophysical study focuses on two adenovirus E1A-interacting proteins, the pRB tumor suppressor and the PCAF histone acetyltransferase.

Ads E1A and HPV16 E7 viral oncoproteins are functionally similar in their ability to bind and inactivate pRB. The residues of HPV 16 E7 that are necessary for stability and for inhibition of pRB function are also necessary for E7 oligomerization. However, the specific oligomerization states of HPV16 E7 and Ad5 E1A as a function of pRB-binding have not been characterized. In part one of this study, HPV16 E7 and Ad5 E1A oligomerization properties are determined using equilibrium sedimentation. Despite the functional similarities between these proteins, the Kd(monomer-dimer) of HPV16 E7 is approximately 100-fold lower than that of a comparable region of Ad5 E1A. Equilibrium sedimentation of pRB/Ad5 E1A and of pRB/HPV16 E7 complexes demonstrate that the association of pRB with the viral oncoproteins does not disturb their inherent oligomerization properties. This study demonstrates differences between the Ad5 E1A and HPV16 E7 oligomerization states that are potentially related to their distinct mechanisms of pRB-inactivation.

In the second part of this study, the 2.3A crystal structure of a PCAF/coenzyme A complex was determined to gain insight into PCAF-mediated histone acetylation. The structure reveals a globular fold with a central protein core at the base of a pronounced cleft that is formed by the N- and C-terminal protein segments. The protein core at the base of this cleft makes extensive contacts with the pantetheine arm of coenzyme A, marking the active site of this enzyme. Correlation of this structure with mutagenesis data for the homologous yeast GCN5 protein implicates this cleft and the N- and C-terminal segments to play an important role in histone binding. Inspection of this histone binding region suggests that a glutamate residue within the protein core plays a catalytic role for histone acetylation. The structure is correlated with other GCN5-related N-acetyltransferases (GNATs) to gain insight into the catalysis and substrate specificity of other GNAT family members.

Notes:

Source: Dissertation Abstracts International, Volume: 62-02, Section: B, page: 0842.

Adviser: Ronen Marmorstein.

Thesis (Ph.D.)--University of Pennsylvania, 2001.

Local Notes:

School code: 0175.

ISBN:

9780493128405

Access Restriction:

Restricted for use by site license.