Hot electron capture dissociation distinguishes leucine from isoleucine in a novel hemoglobin variant, Hb Askew, beta54(D5)Val-->Ile.
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 alpha- and beta-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 beta54Val-->Leu or beta54Val-->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 beta54(D5)Val-->Ile. This is a novel variant, and we have named it Hb Askew.
Williams
Jonathan P
JP
Department of Chemistry, University of Warwick, Coventry, United Kingdom. J.P.Williams@warwick.ac.uk
Creese
Andrew J
AJ
Roper
David R
DR
Green
Brian N
BN
Cooper
Helen J
HJ
D019943:Amino Acid Substitution; D003198:Computer Simulation; D004583:Electrons; D006454:Hemoglobins / Q000737:chemistry*; D006358:Hot Temperature; D007532:Isoleucine / Q000737:chemistry*; D007930:Leucine / Q000737:chemistry*; D008956:Models, Chemical; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*
D006454:Hemoglobins; D007532:Isoleucine; D007930:Leucine