title: Improvement of the Pharmacological Properties of Maize RIP by Cysteine-Specific PEGylation.
abstract: To improve the pharmacological properties of maize ribosome-inactivating protein (maize RIP) for targeting HIV-infected cells, the previously engineered TAT-fused active form of maize RIP (MOD) was further engineered for cysteine-directed PEGylation. In this work, two potential antigenic sites, namely Lys-78 and Lys-264, were identified. They were mutated to cysteine residue and conjugated with PEG5kor PEG20k. The resultant PEG derivatives of MOD variants were examined for ribosome-inactivating activity, circulating half-life and immunogenicity. Our results showed that MOD-PEG conjugates had two- to five-fold lower biological activity compared to the wild-type. Mutation of the two sites respectively did not decrease the anti-MOD IgG and IgE level in mice, but the conjugation of PEG did dramatically reduce the antigenicity. Furthermore, pharmacokinetics studies demonstrated that attachment of PEG20kprolonged the plasma half-life by five-fold for MOD-K78C and 17-fold for MOD-K264C, respectively. The site-specific mutation together with PEGylation therefore generated MOD derivatives with improved pharmacological properties.
authors.affiliation: Centre for Protein Science and Crystallography, School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China. aaky73@yahoo.com.hk.
authors.forename: Ka-Yee
authors.initials: KY
authors.lastname: Au
authors.affiliation: Centre for Protein Science and Crystallography, School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China. Shiww@cuhk.edu.hk.
authors.forename: Wei-Wei
authors.initials: WW
authors.lastname: Shi
authors.affiliation: School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China. silence_qs@163.com.
authors.forename: Shuai
authors.initials: S
authors.lastname: Qian
authors.affiliation: School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China. joanzuo@cuhk.edu.hk.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Zuo
authors.affiliation: Centre for Protein Science and Crystallography, School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China. pcshaw@cuhk.edu.hk.
authors.forename: Pang-Chui
authors.initials: PC
authors.lastname: Shaw
mesh_terms: D000818:Animals; D002460:Cell Line; D003545:Cysteine / Q000737:chemistry*; D006207:Half-Life; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D008810:Mice, Inbred C57BL; D009154:Mutation; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000493:pharmacokinetics / Q000494:pharmacology*; D011092:Polyethylene Glycols / Q000737:chemistry*; D017207:Rats, Sprague-Dawley; D054788:Ribosome Inactivating Proteins / Q000737:chemistry / Q000235:genetics / Q000493:pharmacokinetics / Q000494:pharmacology*; D003313:Zea mays
chemical_list: D007074:Immunoglobulin G; D010940:Plant Proteins; D007073:Immunoglobulin E; D011092:Polyethylene Glycols; D054788:Ribosome Inactivating Proteins; D003545:Cysteine
keywords: MOD; PEGylation; antibody induction; antigenicity; circulation half-life; pharmacokinetics study