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Publication Abstract from PubMed

PEGylated proteins are a mainstay of the biopharmaceutical industry. Although the use of poly(ethylene glycol) (PEG) to increase particle size, stability and solubility is well-established, questions remain as to the structure of PEG-protein conjugates. Here we report the structural characterization of a model beta-sheet protein (plastocyanin, 11.5 kDa) modified with a single PEG 5,000. An NMR spectroscopy study of the PEGylated conjugate indicated that the protein and PEG behaved as independent domains. A crystal structure revealed an extraordinary double-helical assembly of the conjugate, with the helices arranged orthogonally to yield a highly porous architecture. Electron density was not observed for the PEG chain, which indicates that it was disordered. The volume available per PEG chain in the crystal was within 10% of the calculated random coil volume. Together, these data support a minimal interaction between the protein and the synthetic polymer. Our work provides new possibilities for understanding this important class of protein-polymer hybrids and suggests a novel approach to engineering protein assemblies.

Structure of a PEGylated protein reveals a highly porous double-helical assembly.,Cattani G, Vogeley L, Crowley PB Nat Chem. 2015 Oct;7(10):823-8. doi: 10.1038/nchem.2342. Epub 2015 Sep 7. PMID:26391082^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.