Conformations of carp muscle calcium binding parvalbumin

Abstract

Of the two Ca(II) in carp muscle calcium binding parvalbumin B, one may be removed by dialysis against EGTA without significant alteration of the circular dichroism spectra at 224 nm, a result suggesting little or no change in the helical content of 47%. Binding of the two Ca(II) is not cooperative. Addition of a 20-fold or greater excess of EGTA at pH 8.5 results in removal of both Ca(II), reduces the helical content to about 39%, alters only served in Tris buffer at pH 8.5 or bis-tris buffer at pH 6.5.1 Abbreviations used are: Nbs2, 5,5'-dithiobis(2-nitrobenzoic acid); EGTA, ethylene glycol bis(/3-aminoethyl ether)-7V,yV'-tetraacetate. BIOCHEMISTRY,VOL.

Calcium binding sites of rabbit troponin and carp parvalbumin

“…Of the two Ca (II) of parvalbumin, Ca (EF) is overlaid within 0.5 nm by the aromatic side chain of Phe-57. Upon substitution of Ca (II) by terbium (III) and irradiation at 259 nm a characteristic green Tb (III) emission appears, due-to energy transfer from the aromatic side chain of Phe-57 to Tb (EF) [6,9]. Tb (III) emission also occurs upon substitution of the lanthanide ion for Ca (II) in TN-C.…”

Crystallization and structure at 3.2 Å resolution of a terbium parvalbumin

“…The substitution of the two Ca2+ by Tb3+ was performed using a procedure similar to that described in [15]. The extent of replacement was first followed by fluorescence measurement and titration of a parvalbumin solution (0.08 FM) in 30 mM imidazoie, 10 mM NaN3 (pH 6.6) by a solution 6.4 mM TbCl3 in water.…”

“…The determination of this structure at high resolution is interesting for 3 reasons. Firstly, information has been collected using Tb3+ and other lanthanides as luminescence probes in carp [15,16] and cod parvalbumin [17-191 through radiationless energy transfer between aromatic amino acids, excited in their UV absorption bands and the lanthanide which, in this way, is sensitized to emit strongly. Secondly, new methods are developing in macromolecular crystallography.…”

Calcium-binding proteins in the vorticellid spasmoneme

“…Both troponin C and parvalbumin are able to interact with calcium even in the presence of high concentrations of urea (17,35), suggesting that the calcium-protein complex is highly stable and can resist the denaturing effect of strong urea solutions. Troponin C binds calcium in 6 M urea with a small increase in electrophoretic mobility; if, however, the Mg-ATPase inhibitory protein (troponin I) is also present in the calcium-urea gel, the two proteins interact, forming a slower migrating complex (17).…”

“…Thus, both the calciumbinding site(s) and the troponin I recognition site of the troponin C molecule retain their integrity in 6 M urea. Similarly, parvalbumin undergoes a conformational change on addition of calcium in solutions containing 4 M urea (35).…”