Mass spectrometric study of gas-phase ions of acid ß-glucosidase (Cerezyme) and iminosugar pharmacological chaperones.
J Mass Spectrom
; 49(10): 1002-9, 2014 Oct.
Article
em En
| MEDLINE
| ID: mdl-25303390
ABSTRACT
The effect on the conformations and stability of gas-phase ions of Cerezyme, a glycoprotein, when bound to three small-molecule chaperones has been studied using intact ESI MS, collision cross section and MS/MS measurements. To distinguish between the peaks from apo and small-molecule complex ions, Cerezyme is deglycosylated (dg-Cer). ESI MS of dg-Cer reveals that glycosylation accounts for 8.5% of the molecular weight. When excess chaperone, either covalent (2FGF) or noncovalent (A and B iminosugars), is added to solutions of dg-Cer, mass spectra show peaks from 11 chaperone-enzyme complexes as well as free enzyme. On average, ions of the apoenzyme have 1.6 times higher cross sections when activated in the source region of the mass spectrometer. For a given charge state, ions of complexes of 2FGF and B have about 30% and 8.4% lower cross sections, respectively, compared to the apoenzyme. Thus, binding the chaperones causes the gas-phase protein to adopt more compact conformations. The noncovalent complex ions dissociate by the loss of charged chaperones. In the gas phase, the relative stability of dg-Cer with B is higher than that with the A, whereas in solution A binds enzyme more strongly than B. Nevertheless, the disagreement is explained based on the greater number of contacts between the B and dg-Cer than the A and dg-Cer (13 vs. 8), indicating the importance of noncovalent interactions within the protein-chaperone complex in the absence of solvent. Findings in this work suggest a hypothesis towards predicting a consistent correlation between gas-phase properties to solution binding properties.
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Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Imino Açúcares
/
Glucosilceramidase
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
J Mass Spectrom
Assunto da revista:
BIOQUIMICA
Ano de publicação:
2014
Tipo de documento:
Article
País de afiliação:
Reino Unido