The molybdate binding protein Mop from Haemophilus influenzae - Biochemical and thermodynamic characterisation
- Author(s)
- Masters, SL; Howlett, GJ; Pau, RN;
- Details
- Publication Year 2005-07-01,Volume 439,Issue #1,Page 105-112
- Journal Title
- ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS
- Publication Type
- Journal Article
- Abstract
- 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. (C) 2005 Elsevier Inc. All rights reserved.
- Publisher
- ELSEVIER SCIENCE INC
- Keywords
- RESOLUTION CRYSTAL-STRUCTURE; AZOTOBACTER-VINELANDII; ESCHERICHIA-COLI; MOLYBDENUM TRANSPORT; X-RAY; COEFFICIENTS; MOLBINDIN; LIGAND; CRYSTALLIZATION; SPECIFICITY
- Publisher's Version
- https://doi.org/10.1016/j.abb.2005.04.020
- Terms of Use/Rights Notice
- Refer to copyright notice on published article.
Creation Date: 2005-07-01 12:00:00