Witkowska H E, Green B N, Morris M, Shackleton C H
Children's Hospital Oakland Research Institute, California 94609-1809, USA.
Rapid Commun Mass Spectrom. 1995;Spec No:S111-5.
A mutation within the human alpha-globin resulting in an 18 u mass increment was characterized by sequencing the intact M(r) 15000 protein in the gas phase by electrospray ionization tandem mass spectrometry. No separation of the variant protein from its normal counterpart and other components of the hemolysate was performed prior to mass spectrometric analysis. Collision-induced dissociation of the globin molecules carrying 18 protons was affected by their exposure to methane in the collision cell of a triple quadrupole mass spectrometer equipped with an electrospray ion source. Consideration of the major fragmentation ions (b758+, y"284+ and y"617+) narrowed down the mutation site to the last 28 amino acid residues within the protein sequence. Examination of low-abundance product ions allowed the unequivocal identification of the mutation as alpha 136 Leu --> Met, a hemoglobin previously named Hb Chicago.
通过电喷雾电离串联质谱法对气相中完整的相对分子质量为15000的蛋白质进行测序，对导致相对分子质量增加18u的人α-珠蛋白内的一种突变进行了表征。在质谱分析之前，未对变体蛋白与其正常对应物以及溶血产物的其他成分进行分离。携带18个质子的珠蛋白分子在配备电喷雾离子源的三重四极杆质谱仪的碰撞池中暴露于甲烷时，会受到碰撞诱导解离的影响。对主要碎片离子（b758+、y"284+和y"617+）的分析将突变位点缩小到蛋白质序列中的最后28个氨基酸残基。对低丰度产物离子的检测使得能够明确鉴定该突变为α136亮氨酸→甲硫氨酸，这是一种先前命名为Hb Chicago的血红蛋白。
