Structural Studies of the pRB Tumor Suppressor Complexed with Human Papillomavirus E7 Proteins.
Annual rept. 1 Jun 98-31 May 99
WISTAR INST OF ANATOMY AND BIOLOGY PHILADELPHIA PA
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Since viral oncoproteins are expected to compete with and imitate interactions that pRB has with cyclin DI, understanding high affinity pRB-viral oncoprotein complexes will provide tremendous insight into the specific interactions required for the development of small compounds that can destabilize pRB-cyclin DI complexes in cyclin DI-mediated breast cancer. Therefore, the primary goal of this project is to determine the three dimensional structure of pRB bound HPV E7 and Adenovirus 5 ElA. Additionally, since p53 functions as a tumor suppressor that is often inactivated in breast cancer, a secondary goal of this project is to determine the structure of the PCAF acetyltransferase domain with coenzyme A and a p53-derived peptide in order to gain insight into PCAF-mediated p53 activation This study demonstrates that bacterially coexpressed pRB376-792 and viral oncoproteins form complexes These purified complexes probably have resisted crystallization because pRB376-792 includes a flexible linker region between two structured domains of pRB. Therefore, a new linkerless pRB construct has been generated for future pRBviral oncoprotein crystallization trials. Additionally, crystallography of HPVla E7 and NMR studies of Adenovirus S ElA have had preliminary success. The crystal structure of PCAF bound to coenzyme A has been solved and provides insight into PCAF-mediated p53 acetylation and activation.
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