Conformational Engineering of Antibody Fragments on The Surface of Platinum Nanoparticles / 生物化学与生物物理进展

ABSTRACT

ObjectiveRecent successful restoration of the native conformation and function of the complementary-determining regions (CDRs) of antibodies on gold nanoparticles (AuNPs) demonstrates that the era of molecular conformational engineering is dawning. Basically, molecular conformational engineering aims to precisely tune flexible non-functional molecules into special conformations to carry out novel functions, in the same way as protein folding. In order to explore the general applicability of molecular conformational engineering, as well as to reveal the mechanism of protein structure-function relationship, the objective of this work is to restore the native conformation and function of the CDRs of an antibody on platinum nanoparticles (PtNPs). MethodsThe CDR fragment of the anti-lysozyme antibody cAB-lys3, which has no stable conformation or function in free state, was conjugated onto the surface of PtNPs through two Pt-S bonds. The original antigen-recognizing function of the CDR restored on PtNPs was assessed by the specific inhibition of the enzymatic activity of lysozyme by the PtNP-CDR conjugates. ResultsAfter optimization of the peptide density on the surface of PtNPs and modification of PtNPs with polyethylene glycol (PEG), the resulted PtNP-based hybrid artificial antibody (PtNP-10PEG-30P1), dubbed Platinumbody, could bind specifically to lysozyme and significantly inhibit the activity of lysozyme. ConclusionThis is the first time that the fragment of a protein could refold on PtNPs. Together with the previous Goldbody and Silverbody, current work demonstrates that artificial proteins could be generally created by restoration of the native conformation of natural proteins fragments on NPs.