Spectroscopic Evidences for Strong Hydrogen Bonds with Selenomethionine in Proteins

J Phys Chem Lett. 2017 Feb 16;8(4):794-800. doi: 10.1021/acs.jpclett.6b02931. Epub 2017 Feb 2.

Abstract

Careful protein structure analysis unravels many unknown and unappreciated noncovalent interactions that control protein structure; one such unrecognized interaction in protein is selenium centered hydrogen bonds (SeCHBs). We report, for the first time, SeCHBs involving the amide proton and selenium of selenomethionine (Mse), i.e., amide-N-H···Se H-bonds discerned in proteins. Using mass selective and conformer specific high resolution vibrational spectroscopy, gold standard quantum chemical calculations at CCSD(T), and in-depth protein structure analysis, we establish that amide-N-H···Se and amide-N-H···Te H-bonds are as strong as conventional amide-NH···O and amide-NH···O═C H-bonds despite smaller electronegativity of selenium and tellurium than oxygen. It is in fact, electronegativity, atomic charge, and polarizability of the H-bond acceptor atoms are at play in deciding the strength of H-bonds. The amide-N-H···Se and amide-N-H···Te H-bonds presented here are not only new additions to the ever expanding world of noncovalent interactions, but also are of central importance to design new force-fields for better biomolecular structure simulations.

MeSH terms

  • Amides / chemistry
  • Crystallography, X-Ray
  • Hydrogen / chemistry
  • Hydrogen Bonding*
  • Models, Molecular*
  • Nitrogen / chemistry
  • Nuclear Magnetic Resonance, Biomolecular / methods*
  • Oxygen / chemistry
  • Proteins / chemistry*
  • Protons
  • Selenium / chemistry*
  • Selenomethionine / chemistry*

Substances

  • Amides
  • Proteins
  • Protons
  • Hydrogen
  • Selenomethionine
  • Selenium
  • Nitrogen
  • Oxygen