Spectroscopic Evidences for Strong Hydrogen Bonds with Selenomethionine in Proteins

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.

The Se…S/N interactions as a possible mechanism of δ-aminolevulinic acid dehydratase enzyme inhibition by organoselenium compounds: A computational study

“…The simulation of DPDS with the Dmδ-AlaD demonstrated that this organoselenium compound could access the active site making hydrophobic interactions with Arg205, Pro212 (alkyl and phenyl groups), Phe204 and Tyr201 (phenyl and phenyl moieties), besides interacting with Arg217 via H-bond (selenyl and guanidinyl groups [95,96]) (Fig. 4C).…”

Selenoamides modulate dipole–dipole interactions in hydrogen bonded supramolecular polymers of 1,3,5-substituted benzenes

“…[17][18][19][20] In addition, it has been observed both theoretically and experimentally that NHÁ Á ÁS or NHÁ Á ÁSe hydrogen bonds can be as strong as those of NHÁ Á ÁO, despite the lower electronegativity of S and Se. 21,22 In proteins and peptides, the introduction of thioamide or selenoamide bonds has allowed to tune their structure, stability, and -in case of enzymes -activity. [23][24][25][26] Interestingly, as the chalcogen atom in the amide in peptides changes from O to S to Se, the increasing polarizability was found to increasingly dominate the electronic properties of the amides.…”

A Straightforward Access to Stable β‐Functionalized Alkyl Selenols

“…The role of intramolecular interactions in organoselenium compounds has been reviewed . Also, strong Se⋅⋅⋅H−N hydrogen bonds have been reported in proteins with selenomethionine residues . A thorough sampling of protein crystal structures has revealed that for many of them the Se⋅⋅⋅H distances are within the sum of van der Waals radii, 3.1 Å, thus indicating attractive interactions.…”