Poly(N-isopropylacrylamide-co-tris-nitrilotriacetic acid acrylamide) for a combined study of molecular recognition and spatial constraints in protein binding and interactions

J Am Chem Soc. 2014 Sep 10;136(36):12607-14. doi: 10.1021/ja503632w. Epub 2014 Aug 29.

Abstract

Many biological processes require precise regulation and synergy of proteins, and consequently involve molecular recognition and spatial constraints between biomolecules. Here, a library of poly(N-isopropylacrylamide-co-tris-nitrilotriacetic acid acrylamide) (PNTs) has been synthesized and complexed with Cu(2+) in order to serve as models for investigation of the combined effects of molecular recognition and spatial constraints in biomolecular interactions. The average distance between Cu(2+)-trisNTA binding sites in PNTs polymers was varied from 4.3 to 31.5 nm by adjusting their trisNTA contents. His tag (His6), His-tagged enhanced yellow fluorescent protein (His6-eYFP), and His6-tagged collagenase G (His6-ColG), with sizes ranging from 1 to 11 nm, were used as models to assess whether the binding ability is influenced by a cooperative topology based on molecular recognition interactions with Cu(2+)-trisNTA binding sites, and spatial constraints created by decreasing average distance between trisNTAs. His-tagged molecules bound to all PNTs polymers due to their molecular recognition interaction involving histidines and Cu(2+)-trisNTA pockets, but with a binding ability that was highly modulated by the average distance between the trisNTA binding sites. Small molecular mass molecules (His6) exhibit a high binding ability to all PNTs polymers, whereas his-tagged proteins bind to PNTs efficiently only when the average distance between trisNTA binding sites is larger than the protein dimensions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acrylic Resins / chemical synthesis
  • Acrylic Resins / chemistry*
  • Collagenases / chemistry*
  • Collagenases / metabolism
  • Copper / chemistry
  • Histidine / chemistry
  • Luminescent Proteins / chemistry*
  • Models, Molecular
  • Molecular Structure
  • Organometallic Compounds / chemical synthesis
  • Organometallic Compounds / chemistry
  • Protein Binding
  • Thermodynamics

Substances

  • Acrylic Resins
  • Luminescent Proteins
  • Organometallic Compounds
  • Histidine
  • Copper
  • Collagenases