%0 Journal Article
%T A subset of the diverse COG0523 family of putative metal chaperones is linked to zinc homeostasis in all kingdoms of life
%A Crysten E Haas
%A Dmitry A Rodionov
%A Janette Kropat
%A Davin Malasarn
%A Sabeeha S Merchant
%A Val¨¦rie de Cr¨¦cy-Lagard
%J BMC Genomics
%D 2009
%I BioMed Central
%R 10.1186/1471-2164-10-470
%X Based on a combination of comparative genomics, literature and phylogenetic analyses and experimental validations, the COG0523 family can be separated into at least fifteen subgroups. The CobW subgroup involved in cobalamin synthesis represents only one small sub-fraction of the family. Another, larger subgroup, is suggested to play a predominant role in the response to zinc limitation based on the presence of the corresponding COG0523-encoding genes downstream from putative Zur binding sites in many bacterial genomes. Zur binding sites in these genomes are also associated with candidate zinc-independent paralogs of zinc-dependent enzymes. Finally, the potential role of COG0523 in zinc homeostasis is not limited to Bacteria. We have predicted a link between COG0523 and regulation by zinc in Archaea and show that two COG0523 genes are induced upon zinc depletion in a eukaryotic reference organism, Chlamydomonas reinhardtii.This work lays the foundation for the pursuit by experimental methods of the specific role of COG0523 members in metal trafficking. Based on phylogeny and comparative genomics, both the metal specificity and the protein target(s) might vary from one COG0523 subgroup to another. Additionally, Zur-dependent expression of COG0523 and putative paralogs of zinc-dependent proteins may represent a mechanism for hierarchal zinc distribution and zinc sparing in the face of inadequate zinc nutrition.Transition metals perform vital roles in many chemical reactions essential for life. A recent bioinformatic approach suggests Zn-, non-heme Fe- and Cu-proteins constitute 10% of bacterial and eukaryotic proteomes and 13% of archaeal proteomes [1-3]. The roles of these metals can be varied. In some oxidoreductases, for instance, iron and copper are exploited for their ability to accept or donate electrons, while in hemoglobin and hemocyanin, these metals are used for oxygen transport [4-6]. Zinc, on the other hand, serves as an electrophile or Lewis acid in many p
%U http://www.biomedcentral.com/1471-2164/10/470