Positively Charged Mini-Protein Zbasic2 As a Highly Efficient Silica Binding Module: Opportunities for Enzyme Immobilization on Unmodified Silica Supports: Opportunities for enzyme immobilization on unmodified silica supports

Juan M. Bolivar, Bernd Nidetzky*

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

Silica is a highly attractive support material for protein immobilization in a wide range of biotechnological and biomedical-analytical applications. Without suitable derivatization, however, the silica surface is not generally usable for attachment of proteins. We show here that Z basic2 (a three α-helix bundle mini-protein of 7 kDa size that exposes clustered positive charges from multiple arginine residues on one side) functions as highly efficient silica binding module (SBM), allowing chimeras of target protein with SBM to become very tightly attached to underivatized glass at physiological pH conditions. We used two enzymes, d-amino acid oxidase and sucrose phosphorylase, to demonstrate direct immobilization of Z basic2 protein from complex biological samples with extremely high selectivity. Immobilized enzymes displayed full biological activity, suggesting that their binding to the glass surface had occurred in a preferred orientation via the SBM. We also show that charge complementarity was the main principle of affinity between SBM and glass surface, and Z basic2 proteins were bound in a very strong, yet fully reversible manner, presumably through multipoint noncovalent interactions. Z basic2 proteins were immobilized on porous glass in a loading of 30 mg protein/g support or higher, showing that attachment via the SBM combines excellent binding selectivity with a technically useful binding capacity. Therefore, Z basic2 and silica constitute a fully orthogonal pair of binding module and insoluble support for oriented protein immobilization, and this opens up new opportunities for the application of silica-based materials in the development of supported heterogeneous biocatalysts.

Original languageEnglish
Pages (from-to)10040-10049
Number of pages10
JournalLangmuir
Volume28
Issue number26
DOIs
Publication statusPublished - 3 Jul 2012

ASJC Scopus subject areas

  • Electrochemistry
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Materials Science(all)
  • Spectroscopy

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