The crystal structure of Escherichia coli MoeA, a protein from the molybdopterin synthesis pathway

MoeA is involved in synthesis of the molybdopterin cofactor, although its f unction is not yet clearly defined. The three-dimensional structure of the Escherichia coli protein was solved at 2.2 Angstrom resolution. The locatio ns of highly conserved residues among the prokaryotic and eukaryotic MoeA h omologs identifies a cleft in the dimer interface as the likely functional site. Of the four domains of MoeA, domain 2 displays a novel fold and domai ns 1 and 4 each have only one known structural homolog. Domain 3, in contra st, is structurally similar to many other proteins. The protein that resemb les domain 3 most closely is MogA, another protein required for molybdopter in cofactor synthesis. The overall similarity between MoeA and MogA, and th e similarities in a constellation of residues that are strongly conserved i n MoeA, suggests that these proteins bind similar ligands or substrates and may have similar functions. (C) 2001 Academic Press.