Analysis of monoPEGylated human galectin-2 by small-angle x-ray and neutron scattering: concentration dependence of PEG conformation in the conjugate

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dc.contributor.authorHe, LHen_AU
dc.contributor.authorWang, Hen_AU
dc.contributor.authorGaramus, VMen_AU
dc.contributor.authorHanley, TLen_AU
dc.contributor.authorLensch, Men_AU
dc.contributor.authorGabius, HJen_AU
dc.contributor.authorFee, CJen_AU
dc.contributor.authorMiddelberg, APJen_AU
dc.date.accessioned2011-01-18T00:05:56Zen_AU
dc.date.available2011-01-18T00:05:56Zen_AU
dc.date.issued2010-12-01en_AU
dc.date.statistics2010-12-01en_AU
dc.description.abstractProtein conjugation with polyethylene glycol (PEG) is a valuable means for improving stability, solubility, and bioavailability of pharmaceutical proteins. Using human galectin-2 (hGal-2) and 5 kDa PEG as a model system we first produced a PEG-hGal-2 conjugate exclusively at the Cys75 residue, resulting in two monosubstituted subunits per hGal-2 homodimer. Small angle X-ray and neutron scattering (SAXS and SANS) were combined to provide complementary structural information about the PEG-hGal-2 conjugate, wherein signal generation in SAXS depends mainly on the protein while SANS data presents signals from both the protein and PEG moieties. SAXS data gave a constant radius of gyration (Rg = 21.5 Å) for the conjugate at different concentrations and provided no evidence for an alteration of homodimeric structure or hGal-2 ellipsoidal shape upon PEGylation. In contrast, SANS data revealed a concentration dependence of Rg for the conjugate, with the value decreasing from 31.5 Å at 2 mg/mL to 26 Å at 14 mg/mL (based on hGal-2 concentration). Scattering data have been successfully described by the model of the ellipsoidal homogeneous core (hGal-2) attached with polymer chains (PEG) at the surface. Evidently, the PEG conformation of the conjugate strongly depends on conjugate concentration and PEG’s radius of gyration decreases from 24.5 to 15 Å. An excluded volume effect, arising from steric clashes between PEG molecules at high concentration, was quantified by estimating the second virial coefficient, A2, of PEGylated hGal-2 from the SANS data. A positive value of A2 (6.0 ± 0.4 × 10−4 cm3 mol g−2) indicates repulsive interactions between molecules, which are expected to protect the PEGylated protein against aggregation. © 2010 American Chemical Societyen_AU
dc.identifier.citationHe, L., Wang, H., Garamus, V. M., Hanley, T., Lensch, M., Gabius, H.-J., Fee, C. J., & Middelberg, A. (2010). Analysis of monoPEGylated human galectin-2 by small-angle x-ray and neutron scattering: concentration dependence of PEG conformation in the conjugate. Biomacromolecules, 11(12), 3504-3510. doi:10.1021/bm100999aen_AU
dc.identifier.govdoc3130en_AU
dc.identifier.issn1525-7797en_AU
dc.identifier.issue12en_AU
dc.identifier.journaltitleBiomacromoleculesen_AU
dc.identifier.pagination3504-3510en_AU
dc.identifier.urihttp://dx.doi.org/10.1021/bm100999aen_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/2932en_AU
dc.identifier.volume11en_AU
dc.language.isoenen_AU
dc.publisherAmerican Chemical Societyen_AU
dc.subjectSmall angle scatteringen_AU
dc.subjectPolyethylene glycolsen_AU
dc.subjectAbundanceen_AU
dc.subjectProteinsen_AU
dc.subjectMoleculesen_AU
dc.subjectAgglomerationen_AU
dc.titleAnalysis of monoPEGylated human galectin-2 by small-angle x-ray and neutron scattering: concentration dependence of PEG conformation in the conjugateen_AU
dc.typeJournal Articleen_AU
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