Structural studies of the Ni trafficking proteins: HypA and Nur

INOR 25

David C. Kennedy, dkennedy@chem.umass.edu1, Kerrie A. O'Brien1, and Michael J. Maroney, mmaroney@chem.umass.edu2. (1) Department of Chemistry, University of Massachusetts, 710 North Pleasant Street, Amherst, MA 01003, (2) Department of Chemistry, University of Massachusetts-Amherst, 710 N. Pleasant St., Amherst, MA 01003
HypA is an accessory nickel protein that assists in the incorporation of nickel in hydrogenase in Escherichia coli and both urease and hydrogenase in Helicobacter pylori. HypA contains two metal centers, one nickel and one zinc. Both sites have been investigated in H. pylori HypA by XAS. In the absence of Ni, the Zn site is 4-coordinate with a S3(N/O) donor set. Upon coordination of Ni, the Zn site changes to a site containing S4 coordination. This change in coordination is not observed upon reconstitution of the Ni site with Co and may play an important role in discriminating between metal ions within the cell. Mutating the histidine at position two of the protein perturbs both the Ni and Zn binding sites. Mutations to other key residues in H.p. HypA and preliminary structural data of a new Ni responsive transcriptional regulator from Streptomyces coelicolor, Nur, will also be discussed.

 

Bioinorganic Chemistry: Enzymes and Coenzymes
8:30 AM-12:10 PM, Sunday, August 19, 2007 BCEC -- 208, Oral

Division of Inorganic Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007