Role of YfaE in the cofactor assembly and maintenance of Escherichia coli ribonucleotide reductase small subunit

BIOL 133

Chia-Hung Wu, chiahwu@mit.edu, Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, Wei Jiang, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, Carsten Krebs, Departments of Biochemistry and Molecular Biology and of Chemistry, The Pennsylvania State University, University Park, PA 16802, and JoAnne Stubbe, stubbe@mit.edu, Departments of Chemistry and Biology, MIT, 77 Massachusetts Ave, Cambridge, MA 02139.
Ribonucleotide reductases (RNRs) catalyze the conversion of nucleotides to deoxynucleotides, providing precursors essential for DNA replication and repair. Class Ia RNRs are composed of two subunits: R1 (α2) and R2 (β2). R2 contains a diferric-tyrosyl radical cofactor that is essential for nucleotide reduction. The pathway by which cluster assembly occurs inside the cell is still unclear. Examination of the nrdAB operons of 181 genomes revealed a conserved ferredoxin-like protein (29% of the genomes) that is located 3' to nrdB (β2). We have purified this protein, YfaE in E. coli, from inclusion bodies by anaerobic refolding and iron sulfur cluster insertion. UV-vis, EPR, and Mössbauer spectroscopic studies indicate that YfaE contains a [2Fe-2S]1+/2+ cluster. Titration and stopped flow experiments using metβ2 and reduced YfaE suggest that YfaE plays a role in the maintenance and/or assembly of the β2 differic-tyrosyl in vivo.
 

Poster Session
8:00 PM-10:00 PM, Monday, August 20, 2007 BCEC -- Exhibit Hall - B2, Poster

Division of Biological Chemistry

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