Abstract

Napin nIII is a 2S albumin from rapeseed ( Brassica napus L.) homologous to the major mustard allergen. It is composed of two different polypeptide chains linked by two disulphide bonds. The small chain has been isolated by reverse-phase HPLC after reduction of the native protein and its primary structure elucidated. This 37 residue polypeptide contains only two cysteines, at positions 10 and 23, which show a great tendency to form a non-native intramolecular disulphide bridge. The kinetic analysis of this process was performed by measuring the fluorescence emission of the single tryptophan residue of the molecule since its fluorescence intensity is about 30% decreased during disulphide formation. Small changes on the secondary structure of the polypeptide were measured by circular dichroism. The process is delayed in the presence of the reduced large chain of nIII. However, no dimer formation was detected under the conditions used, either between small chains or between the small and the large chains. Thus, the interchain disulphide formation in napin nIII should be considered as an early step during maturation of this multi-subunit seed protein.

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.