Abstract

A pathogenesis-related protein, PR-R from virus-infected tobacco leaves, has been compared in immunological, electrophoretic and chromatographic properties with the sweet protein thaumatin with which it is believed to have ∼ 65% homology of amino acid sequence. PR-R runs faster in PAGE after it has been reduced, and both proteins run slower in SDS PAGE when reduced. PR-R and thaumatin eluted from Superose 12. FPLC columns with apparent M r s of 14 500 and 12 000 respectively, i.e. 68 and 55% of expected values: following reduction and S-carboxymethylation thaumatin eluted with an apparent M r of 48 000. Neither protein in the native state reacts with polyclonal antisera produced against the other protein. Following reduction, cross-reactions can be demonstrated in immunoblots. The results implicate the intramolecular disulphide bridges of both proteins in conferring a compact configuration on the native proteins, rendering some common epitopes inaccessible.

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 call

Disclaimer: 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.