The Interaction of the Lanthanide Ions with Staphylococcal Nuclease
Year: 1973
Type: article
Abstract: The metal ion-binding site of staphylococcal nuclease has been studied at pH 7.0 by using several lanthanide ions. The binding of Gd(III) or Nd(III) to nuclease was associated with tyrosine perturbations in the ultraviolet spectrum which were shown to include tyrosine-85 and tyrosine-115 by using mononitrotyrosine nuclease derivatives. A binding constant of 9 µ m was estimated by spectrophotometric titration of nitrotyrosine-115-nuclease with Gd(III). The Ca(II) required for the binding of nuclease to deoxythymidine 3′,5′-diphosphate-Sepharose could be replaced by Nd(III). Nd(III) stabilized liganded and unliganded nuclease to trypsin digestion. None of the lanthanide ions replaced Ca(II) in the generation of nuclease activity toward DNA under the conditions employed. Kinetic data compatible with a model of competitive inhibition of Ca(II) by La(III), Pr(III), Nd(III), Gd(III), Dy(III), and Yb(III) yielded inhibition constants of 1 to 2 µ m . These data suggest that the lanthanide ions bind tightly to the Ca(II) binding site of nuclease in the presence or absence of substrate or substrate analogue. As does Ca(II), these ions also enhance the binding of substrate analogue to nuclease.
Source: Journal of Biological Chemistry
Institution: National Institutes of Health
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,430
OpenAlex ID: W176161682