Construction of a family of Cys2His2 zinc binding sites in the hydrophobic core of thioredoxin by structure-based design.

Published

Journal Article

A semi-automated, rational design strategy has been used to introduce a family of seven single, mononuclear Cys2His2 zinc sites at various locations in the hydrophobic core of Escherichia colithioredoxin, a protein that is normally devoid of metal centers. The electronic absorption spectra of the CoII complexes show that five of these designed proteins bind metal with the intended tetrahedral geometry. The designed sites differ in their metal-binding constants and effects on protein stability. Since these designs are constructed within the same host protein framework, comparison of their behavior allows a qualitative evaluation of dominant factors that contribute to metal-binding and metal-mediated protein stabilization. Metal-binding constants are dominated by steric interactions between the buried, designed coordination sphere and the surrounding protein matrix. Metal-mediated stability is the consequence of differential binding to the native and unfolded states. Increased interactions with the unfolded state decrease the stabilizing effect of metal binding. The affinity for the unfolded state is dependent on the placement of the primary coordination sphere residues within the linear protein sequence. These results indicate that a protein fold can have a remarkably broad potential for accommodating metal-mediated cross-links and suggest strategies for engineering protein stability by constructing metal sites that maximize metal binding to the native state and minimize binding to the unfolded state.

Full Text

Duke Authors

Cited Authors

  • Wisz, MS; Garrett, CZ; Hellinga, HW

Published Date

  • June 9, 1998

Published In

Volume / Issue

  • 37 / 23

Start / End Page

  • 8269 - 8277

PubMed ID

  • 9622478

Pubmed Central ID

  • 9622478

International Standard Serial Number (ISSN)

  • 0006-2960

Digital Object Identifier (DOI)

  • 10.1021/bi980718f

Language

  • eng

Conference Location

  • United States