Related Experiment Video
Updated: May 26, 2026

LERLIC-MS/MS for In-depth Characterization and Quantification of Glutamine and Asparagine Deamidation in Shotgun Proteomics
Published on: April 9, 2017
Unprecedented occurrence of isoaspartic acid in a plant cyclopeptide
Damien Lacroix1, Soizic Prado, Dennis Kamoga
1Molécules de Communication et Adaptation des Micro-Organismes, UMR 7245 CNRS, Muséum National d'Histoire Naturelle, 63 rue Buffon 75005 Paris, France.
Abstract:
Three structurally related cycloheptapeptides, cyclocitropsides A-C, have been isolated from a MeOH extract of the root bark of Citropsis articulata, a medicinal plant in Uganda. Their sequences were elucidated on the basis of their MS/MS fragmentation, extensive 2D-NMR, chemical degradation, and biochemical modifications. Surprisingly, the sequence of cyclocitropside C differed from that of cyclocitropside B only by an Asp(5)/isoAsp(5) substitution. This is the first report of an isoAsp residue in a plant cyclic peptide.
More Related Videos
11:51Engineering 'Golden' Fluorescence by Selective Pressure Incorporation of Non-canonical Amino Acids and Protein Analysis by Mass Spectrometry and Fluorescence
Published on: April 27, 2018
08:03A Tandem Liquid Chromatography–Mass Spectrometry-based Approach for Metabolite Analysis of Staphylococcus aureus
Published on: March 28, 2017
Related Concept Videos
Allosteric Proteins-ATCase
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Peptide Identification Using Tandem Mass Spectrometry
This technique helps gather information regarding the protein from which the peptide was obtained and to study the peptides’ amino acid sequence. Identifying peptides from a complex mixture is an important component of the growing field of...
Mass Spectrometry: Cycloalkane Fragmentation
For example, cyclohexane molecular ions have a mass-to-charge ratio (m/z) of 84, which tends to produce a stronger signal than linear alkanes like hexane. This stability comes from...