Mass distributions of a macromolecular assembly based on electrospray ionization mass spectrometric masses of the constituent subunits

Journal of biosciences

Franck Zal¹  Leonid Hanin²  Serge Vinogradov4⁴  Brian Green³ 

[1] Equipe d’Ecophysiologie, Station Biologique, UPMC-CNRS-INSU, 29682 Roscoff, France$$;Department of Mathematics, Idaho State University, Pocatello, ID 8085, USA$$;Micromass UK Ltd., Altrincham, Cheshire, WA14 5R2, UK$$;Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, MI 48201, USA$$

关键词: Electrospray ionization mass spectrometry;    erythrocruorin;    lumbricus;    mass distribution;    riftia;   

DOI  :  

来源: Indian Academy of Sciences

【 摘 要 】

Macromolecular assemblies containing multiple protein subunits and having masses in the megadalton (MDa) range are involved in most of the functions of a living cell. Because of variation in the number and masses of subunits, macromolecular assemblies do not have a unique mass, but rather a mass distribution. The giant extracelular erythrocruorins (Ers), ∼ 3.5 MDa, comprized of at least 180 polypeptide chains, are one of the best characterized assemblies. Three-dimensional reconstructions from cryoelectron microscopic images show them to be hexagonal bilayer complexes of 12 subassemblies, each comprised of 12 globin chains, anchored to a subassembly of 36 nonglobin linker chains. We have calculated the most probable mass distributions for Lumbricus and Riftia assemblies and their globin and linker subassemblies, based on the Lumbricus Er stoichiometry and using accurate subunit masses obtained by electrospray ionization mass spectrometry. The expected masses of Lumbricus and Riftia Ers are 3.517 MDa and 3.284 MDa, respectively, with a possible variation of ∼ 9% due to the breadth of the mass distributions. The Lumbricus Er mass is in astonishingly good agreement with the mean of 23 known masses, 3.524 ± 0.481 MDa.

【 授权许可】

Unknown