Hot Electron Capture Dissociation Distinguishes Leucine from Isoleucine in a Novel Hemoglobin Variant, Hb Askew, β54(D5)Val→Ile

• Published in: Journal of the American Society for Mass Spectrometry 2009-09, Vol.20 (9), p.1707-1713
• Main Authors: Williams, Jonathan P., Creese, Andrew J., Roper, David R., Green, Brian N., Cooper, Helen J.
• Format: Article
• Language: English
• Subjects: Amino acids; Analytical Chemistry; Beta decay; Bioinformatics; Biotechnology; Chains; Chemistry; Chemistry and Materials Science; Cyclotron resonance; Electron capture; Energy consumption; Energy of dissociation; Fourier transforms; Hemoglobin; Ions; Leucine; Mass spectrometry; Organic Chemistry; Proteomics
• ISSN: 1044-0305; 1879-1123
• DOI: 10.1016/j.jasms.2009.05.002

Population migration has led to the global dispersion of human hemoglobinopathies and has precipitated a need for their identification. An effective mass spectrometry-based procedure involves analysis of the intact α- and β-globin chains to determine their mass, followed by location of the variant amino acid residue by direct analysis of the enzymatically digested chains and low-energy collision induced dissociation of the variant peptide. Using this procedure, a variant was identified as either β54Val→Leu or β54Val→Ile, since the amino acids leucine and isoleucine cannot be distinguished using low-energy collisions. Here, we describe how hot electron capture dissociation on a Fourier transform-ion cyclotron resonance mass spectrometer was used to distinguish isoleucine from leucine and identify the mutation as β54(D5)Val→Ile. This is a novel variant, and we have named it Hb Askew. The novel hemoglobin variant, β54Val→Ile, has been determined by hot electron capture dissociation (HECD).