tailieunhanh - Thermal Stability of RNA Phage Virus-Like Particles Displaying Foreign Peptides

Background: To be useful for genetic display of foreign peptides a viral coat protein must tolerate peptide insertions without major disruption of subunit folding and capsid assembly. The folding of the coat protein of RNA phage MS2 does not normally tolerate insertions in its AB-loop, but an engineered single-chain dimer readily accepts them as long as they are restricted to one of its two halves. Results: Here we characterize the effects of peptide insertions on the thermal stabilities of MS2 virus-like particles (VLPs) displaying a variety of different peptides in one AB-loop of the coat protein single-chain dimer. These particles. | Caldeira and Peabody Journal of Nanobiotechnology 2011 9 22 JOURNAL OF NANOBIOTECHNOLOGY http content 9 1 22 RESEARCH Open Access Thermal Stability of RNA Phage Virus-Like Particles Displaying Foreign Peptides Jerri C Caldeira and David S Peabody Abstract Background To be useful for genetic display of foreign peptides a viral coat protein must tolerate peptide insertions without major disruption of subunit folding and capsid assembly. The folding of the coat protein of RNA phage MS2 does not normally tolerate insertions in its AB-loop but an engineered single-chain dimer readily accepts them as long as they are restricted to one of its two halves. Results Here we characterize the effects of peptide insertions on the thermal stabilities of MS2 virus-like particles VLPs displaying a variety of different peptides in one AB-loop of the coat protein single-chain dimer. These particles typically denature at temperatures around 5-10 C lower than unmodified VLPs. Even so they are generally stable up to about 50 C. VLPs of the related RNA phage PP7 are cross-linked with intersubunit disulfide bonds and are therefore significantly more stable. An AB-loop insertion also reduces the stability of PP7 VLPs but they only begin to denature above about 70 C. Conclusions VLPs assembled from MS2 single-chain dimer coat proteins with peptide insertions in one of their AB-loops are somewhat less stable than the wild-type particle but still resist heating up to about 50 C. Because they possess disulfide cross-links PP7-derived VLPs provide an alternate platform with even higher stability. Background We recently described a method for peptide presentation on virus-like particles VLPs of the RNA bacteriophage MS2 which we believe offers several advantages over other display systems for certain applications 1-3 . Peptides are inserted by recombinant DNA methods into a surface loop of coat protein. When expressed from a plasmid in bacteria the resulting VLPs .

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