Poster abstracts
Poster number 34 submitted by Pearson Maugeri
Using resonance raman spectroscopy to elucidate metal incorporation of R2lox, a novel heterobimetallic oxidase
Pearson T. Maugeri (Biophysics), Nicholas E. Trivelas (Department of Chemistry and Biochemistry, Ohio State University), Effie C. Kisgeropoulos (Ohio State Biochemistry Program)
Abstract:
One of the most common bioinorganic motifs present in nature is the non-heme, bimetallic cofactors coordinated within an α-helical protein. These proteins carry out interesting and diverse chemistry, from iron storage to 1- and 2-electron redox reactions. However, until recently, it was thought that these proteins contained only Fe/Fe bimetallic sites; it wasn’t until recently that both a functional Mn/Mn and heterobimetallic Mn/Fe protein was identified. Within the Mn/Fe group, R2-like ligand-binding oxidase (R2lox) represents a new class of protein that utilizes the Mn/Fe moiety to do catalysis. R2lox has been identified in Mycobacterium tuberculosis as well as several other pathogenic bacteria, and is particularly noteworthy due to its upregulation in the virulent strain of M. tuberculosis. The above considerations make R2lox an attractive target for tuberculosis therapeutics. However, very little is known about R2lox. The heterobimetallic cofactor spontaneously assembles in vitro in the presence of air, running counter to the well-established Irving-Williams series for metal-binding affinities; furthermore, while the protein is isolated with a fatty acid bound to the active site, the specific function of R2lox remains unknown. One outstanding question we seek to address is the mechanism of metal incorporation. To do this, we are making use of a state-of-the-art resonance Raman (rR) spectroscopy setup combined with isotopic substitution and multi-wavelength studies to probe the vibrational and electronic structure of the R2lox active site.
References:
Jiang, W., et al. A manganese(IV)/Iron(III) cofactor in Chlamydia trachomatis ribonucleotide reductase. Science 2007<>, 316, 1188-1191.
Andersson, C. and Högbom. A Mycobacterium tuberculosis ligand-binding protein reveals a new cofactor in a remodeled R2-protein scaffold. PNAS 2009, 106, 5633-5638.
Griese, J. G. et al. Direct observation of structurally encoded metal discrimination and ether bond formation in a heterodinuclear metalloprotein. PNAS 2013, 110, 17189-17194.
Keywords: R2lox, metal incorporation, resonance Raman spectroscopy