title: Extended X-ray absorption fine structure studies on periplasmic and intracellular molybdenum-binding proteins.
abstract: We have studied the molybdenum K-edge X-ray absorption spectra of Mo bound in the Mo-binding proteins Mop from Haemophilus influenzae, ModG from Azotobacter vinelandii and the Escherichia coli ModE transcriptional regulatory protein, and compared them with the absorption spectra of A. vinelandii ModA and monomeric molybdate. Pre-edge and extended fine structure data indicate that the Mo-binding proteins with molbindin-like domains bind tetrahedral molybdate with a Mo-O distance of 1.76 A. The molbindin subunits or sub-domains represent a novel protein fold that is used by proteins with distinct functions to bind molybdate in the cytoplasm. The high specificity of the proteins for molybdenum does not depend on a change of coordination number or geometry.
authors.affiliation: Department of Chemistry, The University of York, Heslington York YO10 5DD, UK. akd1@york.ac.uk
authors.forename: A K
authors.initials: AK
authors.lastname: Duhme
authors.forename: W
authors.initials: W
authors.lastname: Meyer-Klaucke
authors.forename: D J
authors.initials: DJ
authors.lastname: White
authors.forename: L
authors.initials: L
authors.lastname: Delarbre
authors.forename: L A
authors.initials: LA
authors.lastname: Mitchenall
authors.forename: R N
authors.initials: RN
authors.lastname: Pau
mesh_terms: D016948:Azotobacter vinelandii / Q000737:chemistry; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D002352:Carrier Proteins / Q000737:chemistry*; D004926:Escherichia coli / Q000737:chemistry; D006193:Haemophilus influenzae / Q000737:chemistry*; D047908:Intracellular Signaling Peptides and Proteins; D008982:Molybdenum / Q000737:chemistry* / Q000378:metabolism; D017433:Protein Structure, Secondary; D013057:Spectrum Analysis
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; C101049:ModG protein, Azotobacter vinelandii; D008982:Molybdenum