Protein prosthesis: β-peptides as reverse-turn surrogates

Protein Sci. 2013 Mar;22(3):274-9. doi: 10.1002/pro.2208. Epub 2013 Jan 17.

Abstract

The introduction of non-natural modules could provide unprecedented control over folding/unfolding behavior, conformational stability, and biological function of proteins. Success requires the interrogation of candidate modules in natural contexts. Here, expressed protein ligation is used to replace a reverse turn in bovine pancreatic ribonuclease (RNase A) with a synthetic β-dipeptide: β²-homoalanine-β³-homoalanine. This segment is known to adopt an unnatural reverse-turn conformation that contains a 10-membered ring hydrogen bond, but one with a donor-acceptor pattern opposite to that in the 10-membered rings of natural reverse turns. The RNase A variant has intact enzymatic activity, but unfolds more quickly and has diminished conformational stability relative to native RNase A. These data indicate that hydrogen-bonding pattern merits careful consideration in the selection of beneficial reverse-turn surrogates.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aminobutyrates / chemistry*
  • Animals
  • Asparagine / analogs & derivatives
  • Asparagine / chemistry
  • Cattle
  • Circular Dichroism
  • Dipeptides / chemistry*
  • Dipeptides / genetics
  • Dipeptides / metabolism
  • Enzyme Stability
  • Hydrogen Bonding
  • Kinetics
  • Nipecotic Acids / chemistry
  • Peptide Fragments / chemistry*
  • Peptide Fragments / genetics
  • Peptide Fragments / metabolism
  • Proline / analogs & derivatives
  • Proline / chemistry
  • Protein Splicing
  • Protein Structure, Secondary
  • Protein Unfolding
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism
  • Ribonuclease, Pancreatic / chemistry*
  • Ribonuclease, Pancreatic / genetics
  • Ribonuclease, Pancreatic / metabolism
  • Stereoisomerism
  • Transition Temperature

Substances

  • Aminobutyrates
  • Dipeptides
  • Nipecotic Acids
  • Peptide Fragments
  • Recombinant Proteins
  • nipecotic acid
  • Asparagine
  • alpha-aminobutyric acid
  • Proline
  • Ribonuclease, Pancreatic