Fragmentation of Peptoids Containing a Basic Residue
Poster Number
19A
Introduction/Abstract
Peptoids, also referred to as poly (N-substituted glycines) belong to a class of peptidomimetic polymers whose side chain is appended to the nitrogen atom of the peptoid backbone as opposed to the ɑ-carbon in peptides. This structural difference gives the compound several advantages such as enhanced structural flexibility and proteolytic stability. Peptoids as a peptidomimetic play an important role in advancing drug development and polymeric science. The applications of these synthetic compounds call for the development of analytical methods to characterize the sequence and structural features of peptoids associated with combinatorial libraries that allow functionalized monomers to be arranged in an array of desired sequences.; however, research is limited. The current study focuses on analyzing the fragmentation characteristics of model peptoids in tandem mass spectrometry experiments. Model peptoids with basic side chains used in this study are synthesized by solid phase chemistry using a repeating two-step reaction cycle on Rink amide resin. One group of peptoids are acetylated at the N-terminus and the other group are nonacetylated. Tandem mass spectrometry experiments are carried out in a linear quadrupole mass spectrometer (LTQ XLTM) and a conventional triple quadrupole mass spectrometer (Varian 320). The peptoids are ionized via electrospray ionization. The charged peptoids are fragmented through collision induced dissociation (MS/MS) experiments. The resulting MS/MS spectra are analyzed by comparing the abundance of B and Y fragment ions to understand the mechanism of fragmentation. The results show that all singly charged peptoids display a greater abundance of Y ions than that of B ions. The position of the basic residue along the peptoid backbone appears to have minimal influence on overall fragmentation patterns; however, it does enhance the formation of certain ions. In comparing the acetylated and nonacetylated peptoids, a few interesting features have been observed. The presence of the acetyl group enhances high mass Y8 formation, while nonacetylated peptoids produce a high abundance of Y7 ions. The results support our proposed fragmentation mechanism that an oxazolone ring is an important intermediate.
Location
Library and Learning Center, 3601 Pacific Ave., Stockton, CA 95211
Format
Poster Presentation
Fragmentation of Peptoids Containing a Basic Residue
Library and Learning Center, 3601 Pacific Ave., Stockton, CA 95211
Peptoids, also referred to as poly (N-substituted glycines) belong to a class of peptidomimetic polymers whose side chain is appended to the nitrogen atom of the peptoid backbone as opposed to the ɑ-carbon in peptides. This structural difference gives the compound several advantages such as enhanced structural flexibility and proteolytic stability. Peptoids as a peptidomimetic play an important role in advancing drug development and polymeric science. The applications of these synthetic compounds call for the development of analytical methods to characterize the sequence and structural features of peptoids associated with combinatorial libraries that allow functionalized monomers to be arranged in an array of desired sequences.; however, research is limited. The current study focuses on analyzing the fragmentation characteristics of model peptoids in tandem mass spectrometry experiments. Model peptoids with basic side chains used in this study are synthesized by solid phase chemistry using a repeating two-step reaction cycle on Rink amide resin. One group of peptoids are acetylated at the N-terminus and the other group are nonacetylated. Tandem mass spectrometry experiments are carried out in a linear quadrupole mass spectrometer (LTQ XLTM) and a conventional triple quadrupole mass spectrometer (Varian 320). The peptoids are ionized via electrospray ionization. The charged peptoids are fragmented through collision induced dissociation (MS/MS) experiments. The resulting MS/MS spectra are analyzed by comparing the abundance of B and Y fragment ions to understand the mechanism of fragmentation. The results show that all singly charged peptoids display a greater abundance of Y ions than that of B ions. The position of the basic residue along the peptoid backbone appears to have minimal influence on overall fragmentation patterns; however, it does enhance the formation of certain ions. In comparing the acetylated and nonacetylated peptoids, a few interesting features have been observed. The presence of the acetyl group enhances high mass Y8 formation, while nonacetylated peptoids produce a high abundance of Y7 ions. The results support our proposed fragmentation mechanism that an oxazolone ring is an important intermediate.
