Studying the folding propensity of asparagine-containing peptides in a molecular beam

Blodgett, Karl N.

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https://hdl.handle.net/2142/100679 Copy

Description

Title

Studying the folding propensity of asparagine-containing peptides in a molecular beam

Author(s)

Blodgett, Karl N.

Contributor(s)

• Zwier, Timothy S.
• Sun, Dewei
• Fischer, Joshua L.

Issue Date

2018-06-20

Keyword(s)

Conformers and isomers

Abstract

Asparagine (Asn) and Glutamine (Gln) are the only two naturally-occuring amino acids that incorporate an amide group in the side chain, differing only by a single methylene group that lengthens the chain in Gln relative to Asn. These two amino acids appear with unusual abundance in the prion forming domain of proteins that are implicated in neurodegenerative disease pathogenesis. In a bottom-up approach towards understanding nature’s preference for Asn and Gln in prion domains, we build off of our previous study of Gln-containing peptides by elucidating the inherent folding propensities of three Asn-containing peptides: Ac-Asn-NHBn, Ac-Ala-Asn-NHBn, and Ac-Asn-Asn-NHBn. These molecules are brought into the gas phase by laser desorption and cooled in a supersonic expansion before interrogation via resonant two-photon ionization (R2PI), IR-UV holeburning, and resonant ion-dip infrared (RIDIR) spectroscopies. This talk will describe the conformation-specific IR and UV spectroscopy of these three peptides, concentrating on the fundamental question of whether side-chain/side-chain, backbone/backbone, or side-chain/backbone interactions are preferred in each case. Assignment of the observed conformations are deduced from a comparison of the experimental IR spectra with the predictions of calculations. Two unique conformational isomers are assigned to the capped Asn amino acid while only one conformational isomer is present in both dipeptides. These structures will be compared with those found in the analogous glutamine-containing peptides. Best fit calculated structures reveal intriguing incipient secondary structure formation at the first possible instance.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Permalink

http://hdl.handle.net/2142/100679

DOI

10.15278/isms.2018.WJ09

Copyright and License Information

Copyright 2018 Karl N. Blodgett

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