Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0348321 (Haemophilus)
 15,372 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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.
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PMID:Extended X-ray absorption fine structure studies on periplasmic and intracellular molybdenum-binding proteins. 1055 Jun 87

The protein Mop from Haemophilus influenzae is a member of the molbindin family of proteins. Using isothermal titration calorimetry (ITC), Mop was observed to bind molybdate at two distinct sites with a stoichiometry of 8 mol molybdate per Mop hexamer. Six moles of molybdate bound endothermically at high affinity sites (K(a)=8.5 x 10(7)M(-1)), while 2 mol of molybdate bound exothermically at lower affinity sites (K(a)=3.7 x 10(7)M(-1)). Sulphate was also found to bind weakly at the higher affinity sites. ITC revealed that the affinity of molybdate binding to the endothermic site decreased with increasing pH and was accompanied by the transfer from the buffer to the protein of one proton per Mop monomer. These kinetic and thermodynamic results are interpreted with reference to molbindin crystal structures and data concerning molbindin binding affinities. Mop binds molybdate with high specificity, capacity, and affinity which indicates that Mop has a role as an intracellular molybdate binding protein involved in oxyanion homeostasis.
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PMID:The molybdate binding protein Mop from Haemophilus influenzae--biochemical and thermodynamic characterisation. 1594 40