Spectroscopic Signature of a Ubiquitous Metal Binding Site in the Metallo-beta-Lactamase Superfamily

V.A. CAMPOS; J.M. GONZALEZ; D.L. TIERNEY; A.J. VILA

JOURNAL OF BIOLOGICAL INORGANIC CHEMISTRY

SPRINGER

Lugar: Heidelberg; Año: 2010 vol. 15 p. 1209 - 1218

0949-8257

The metallo-b-lactamase (MbL) superfamily isa functionally diverse group of metalloproteins sharing adistinctive ab/ab fold and a characteristic metal bindingmotif. A large number of open reading frames identifiedin genomic sequencing efforts have been annotated asmembers of this superfamily through sequence comparisons.However, structural and functional studies performedon purified proteins are normally needed tounequivocally include a newly discovered protein in theMbL superfamily. Here we report the spectroscopiccharacterization of recombinant YcbL, a gene productannotated as a member of the MbL superfamily whosefunction in vivo remains unknown. By taking advantageof the structural features characterizing the MbL superfamilymetal binding motif, we performed spectroscopicstudies on Zn(II)- and Co(II)-substituted YcbL to structurallyinterrogate the metal binding site. The dinuclearcenter in Co(II)-YcbL was shown to display characteristicelectronic absorption features in the visible region, whichwere also observed in an engineered MbL aimed atmimicking this metal site. Thus, the spectroscopic featuresreported herein can be employed as a signature to readilyidentify and characterize the presence of these ubiquitousmetal binding sites.