Experimental procedures such as X-ray diffraction are key in the development of three dimensional structures representing several protein molecules. However, the three dimensional structures of some proteins have yet to be determined. Adenosine G-protein coupled receptor A2a is an example of a protein whose molecular structure does not exist within the protein database. We attempt to find out the three dimensional structure of A2a using the Homology modeling program “Modeller”.

1. Construction of an A2aGPCR Model using Homology Comparative Protein Modeling Gabrielle Roberts Biology Department, Long Island University, Brooklyn, NY

6. Protein Structural levels Primary structure Secondary structure Tertiary structure Quaternary structure Polypeptide chain Alpha helix or beta sheets Functional protein* Interactions between more than one polypeptide

8. Parallel Anti-Parallel

12. Serum albumin Homo sapiens Pilin Neisseria gonorrhoeae

21. A2a Theoretical Model vs. A2b Model Models viewed using Ras win