Miniature homeodomains: high specificity without an N-terminal arm

J Am Chem Soc. 2003 Mar 26;125(12):3416-7. doi: 10.1021/ja028628s.

Abstract

Recently, we described a strategy for the design of miniature proteins that bind DNA and protein surfaces with high affinity and selectivity. This strategy involves identifying the functional epitope required for macromolecular recognition by a natural protein and presenting it on a small, stable protein scaffold. In previous work, high-affinity DNA recognition was achieved only when the miniature protein contained the complete functional epitope. Here we report a miniature homeodomain that recognizes its 6-bp target site in the nanomolar concentration range at 25 degrees C, despite the absence of DNA contact residues located along the homeodomain N-terminal arm. We conclude that miniature proteins can achieve high affinity and selectivity for DNA by design even when the functional epitope is incomplete by using pre-organization to effectively compensate for lost protein-DNA contacts. In this case it has been possible to miniaturize both the recognition surface and the structural framework of a globular protein fold.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • DNA / chemistry
  • DNA / metabolism
  • Homeodomain Proteins / chemistry*
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / metabolism
  • Molecular Sequence Data
  • Pancreatic Polypeptide / chemistry*
  • Pancreatic Polypeptide / genetics
  • Pancreatic Polypeptide / metabolism
  • Protein Conformation
  • Protein Structure, Secondary
  • Substrate Specificity

Substances

  • Homeodomain Proteins
  • pancreatic polypeptide, avian
  • Pancreatic Polypeptide
  • DNA