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 PEG5k or 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 PEG20k prolonged 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.
Highlights
Ribosome-inactivating proteins (RIPs) are RNA N-glycosidases that remove a specific adenine at the α-sarcin/ricin loop (SRL) of large ribosomal RNA and in turn cease protein synthesis [1,2].RIPs are categorized into three types according to their structural organization
We have recently fused the HIV-1 TAT transduction peptide to the N-termini of maize RIP and exploited its unique activity regulatory feature of maturation by introducing HIV-1 protease recognition sequences to the internal inactivation region to sensitize maize RIP towards HIV-infected cells, in which the activation of maize
This study aimed to improve the therapeutic potential of maize RIP by cysteine-directed
Summary
Ribosome-inactivating proteins (RIPs) are RNA N-glycosidases that remove a specific adenine at the α-sarcin/ricin loop (SRL) of large ribosomal RNA (rRNA) and in turn cease protein synthesis [1,2]. RIPs are categorized into three types according to their structural organization. Type 2, such as ricin and abrin [5], is heterodimeric with an enzymatically active A chain linked to a lectin-like B chain by a disulphide bond. Maize RIP is a type 3 RIP, which is first synthesized with an extra 25-amino-acid internal segment and requires proteolytic removal upon which the precursor is activated to resume N-glycosidase function [6,7]. We have recently fused the HIV-1 TAT transduction peptide to the N-termini of maize RIP and exploited its unique activity regulatory feature of maturation by introducing HIV-1 protease recognition sequences to the internal inactivation region to sensitize maize RIP towards HIV-infected cells, in which the activation of maize
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
