Download MendeleyCrystal structure of a bifunctional transformylase and cyclohydrolase enzyme in purine biosynthesis.
Greasley, S.E., Horton, P., Ramcharan, J., Beardsley, G.P., Benkovic, S.J., Wilson, I.A.(2001) Nat Struct Biol 8: 402-406
- PubMed: 11323713
- DOI: https://doi.org/10.1038/87555
- Primary Citation of Related Structures:
1G8M - PubMed Abstract:
ATIC, the product of the purH gene, is a 64 kDa bifunctional enzyme that possesses the final two activities in de novo purine biosynthesis, AICAR transformylase and IMP cyclohydrolase. The crystal structure of avian ATIC has been determined to 1.75 A resolution by the MAD method using a Se-methionine modified enzyme. ATIC forms an intertwined dimer with an extensive interface of approximately 5,000 A(2) per monomer. Each monomer is composed of two novel, separate functional domains. The N-terminal domain (up to residue 199) is responsible for the IMPCH activity, whereas the AICAR Tfase activity resides in the C-terminal domain (200-593). The active sites of the IMPCH and AICAR Tfase domains are approximately 50 A apart, with no structural evidence of a tunnel connecting the two active sites. The crystal structure of ATIC provides a framework to probe both catalytic mechanisms and to design specific inhibitors for use in cancer chemotherapy and inflammation.
Organizational Affiliation:
Department of Molecular Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, USA.
