Acta Crystallographica Section F

Structural Biology and Crystallization Communications

Volume 64, Part 4 (April 2008)

crystallization communications

 

Crystallization of hepatocyte nuclear factor 4 (HNF4) in complex with the HNF1 promoter element

P. Lu, J. Liu, M. Melikishvili, M. G. Fried and Y.-I. Chi

Abstract: Hepatocyte nuclear factor 4 (HNF4) is a member of the nuclear receptor superfamily that plays a central role in organ development and metabolic functions. Mutations on HNF4 cause maturity-onset diabetes of the young (MODY), a dominant monogenic cause of diabetes. In order to understand the molecular mechanism of promoter recognition and the molecular basis of disease-causing mutations, the recombinant HNF4 DNA-binding domain was prepared and used in a study of its binding properties and in crystallization with a 21-mer DNA fragment that contains the promoter element of another MODY gene, HNF1. The HNF4 protein displays a cooperative and specific DNA-binding activity towards its target gene-recognition elements. Crystals of the complex diffract to 2.0 Å using a synchrotron-radiation source under cryogenic (100 K) conditions and belong to space group C2, with unit-cell parameters a = 121.63, b = 35.43, c = 70.99 Å, = 119.36°. A molecular-replacement solution has been obtained and structure refinement is in progress. This structure and the binding studies will provide the groundwork for detailed functional and biochemical studies of the MODY mutants.

Keywords: protein-DNA complex; gel-shift assay; diabetes; nuclear receptors; zinc-finger proteins.

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