Understanding how metal binding regulates the activity of the diphtheria toxin repressor protein (DtxR) requires information about the structure in solution. We have prepared a DtxR mutant construct with three additional N-terminal residues, Gly-Ser-His-DtxR(Cys-102 --> Asp), that retains metal-binding capabilities, but remains monomeric in solution and does not bind DNA under conditions that e...

BACKGROUND Selective recognition and binding of IgG molecules is the basis for a host of immunological and affinity purification techniques. Capture of an IgG in these procedures relies chiefly on its interaction with one of a variety of reengineered bacterial receptors which bind to the Fc region of IgG molecules with very high affinity. While this interaction is extremely efficient in trappin...

The structure of inositol monophosphatase has been determined to 2.60 A resolution in complexes with Mn2+ and with Mn2+ and phosphate. In the Mn2+ complex, three metal cations and one Cl were bound in the active site on each of the two subunits of the enzyme. Ligands to the three metals include the side chains of Glu 70, Asp 90, Asp 93, and Asp 220, t he carbonyl group of Ile 92, several solven...

The tightly binding and readily exchanging metal binding sites in the active site of bovine lens leucine aminopeptidase (blLAP; EC 3.4.11.1) have been differentiated and identified by x-ray crystallography. In native blLAP,Zn2+ occupies both binding sites. In solution, site 1 readily exchanges Zn2+ for other divalent cations, including Mg2+. The Zn2+ in site 2 is unavailable for metal exchange ...

Concanavalin A (con A) is a saccharide-binding protein of the Jack bean [ 11. The protein contains two different metal-binding sites, which must be occupied in order for saccharide binding to be possible [2,3]. When the metal ions are removed by acid treatment, the demetallized protein can bind only divalent transition metal ions (Mn”, Co”, Ni2+, Zn”, or Cd23 at a site designated S 1, but it ca...

Metal ion binding to the insulin hexamer has been investigated by crystallographic analysis. Cadmium, lead, and metal-free hexamers have been refined to R values of 0.181, 0.172, and 0.172, against data of 1.9-, 2.5-, and 2.5-A resolution, respectively. These structures have been compared with each other and with the isomorphous two-zinc insulin. The structure of the metal-free hexamer shows th...

Terbium was used as a probe of Ca2+-binding sites on the prothrombin-phospholipid complex. Stoichiometric titrations of prothrombin binding to phospholipid vesicles with either Tb3+ or Ca2+ showed that a minimum of 8 metal ions were needed for binding prothrombin to vesicles (3 Mn2+ + 5 Ca2+ for prothrombin or 8 Tb3+ for F-1). When Ca2+ alone was used, a total of about 11 metal ions were needed...

Using spin-polarized density functional theory calculations, we study binding properties of small metal nanoclusters (Cu(13) and Al(13)) onto carbon nanotubes (CNTs). On defect-free CNTs, the binding affinity with the Cu or Al cluster is very weak. When various defects such as vacancies, substitutional nickel defects, and nickel adatoms are introduced in CNTs to increase the binding strength, t...

few novel cobalt(ii) and copper(ii) complexes [m(fmp)3]cl2, [m(fmp)(bpy)2]cl2,[m(fmp)(phen)2]cl2 and [m(fmp)(phen)(bpy)]cl2 (fmp = 3-furan-2-ylmethylene-pentane-2,4-dione, phen = 1,10-phenanthroline, bpy = 2,2'-bipyridine) have been synthesized andcharacterized by elemental analyses, molar conductance, magnetic susceptibility measurements,ir, electronic, epr, mass spectra and cyclic voltam...