Abstract
The yeast ascospore wall consists of four morphologically distinct layers. The hydrophobic surface layers are biogenically derived from the prospore wall and appear dark after OsO4 staining. They seem to be responsible for the stability of the spores against attack by lytic enzymes. By amino acid analysis of acid hydrolysates of ascospore walls, two new peaks were detected, which were shown to be the racemic and meso form, respectively, of dityrosine. The identity of this hitherto unknown component of the yeast ascospore wall with standard dityrosine was proven by 1H NMR and by mass spectrometry. A 13C NMR spectroscopic investigation of the structure of dityrosine confirmed that, in natural dityrosine, the biphenyl linkage is located ortho, ortho to the hydroxyl groups. Following digestion of the inner layers of isolated ascospore walls it was shown that dityrosine is very probably located only in the surface layers. The same conclusion was reached independently by an investigation of spores of a strain homozygous for the mutation gcn1, which lack the outermost layers of the spore wall and were practically devoid of dityrosine. In sporulating yeast, L-tyrosine was readily incorporated into the dityrosine of the ascospore wall. Control experiments involving vegetative a/alpha cells and nonsporulating alpha/alpha cells under sporulation conditions showed that dityrosine is indeed sporulation-specific.
Highlights
From the SInstitut fur Allgemeine Biochemieand Ludwig Boltzmann-Forschungsstellefur Biochemie, BZnstitutfur Organische Chemie, and §Znstitutfur Virologie, A-1090 Wien, Austria
By amino acid analysis of acid hydrolysates of ascospore walls,twonew peaks were detected, which were shown to bethe racemicand meso form, respectively, of dityrosine
Dityrosine was found in acid hydrolysates of a number of biological materials such as tussahsilk fibroin [2], insect cuticular resilin [3, 4],the spore coat of Bacillus subtilis ( 5 ),and thefertilization membrane of the sea urchin egg [6]
Summary
From the SInstitut fur Allgemeine Biochemieand Ludwig Boltzmann-Forschungsstellefur Biochemie, BZnstitutfur Organische Chemie, and §Znstitutfur Virologie, A-1090 Wien, Austria. Dityrosine was found in acid hydrolysates of a number of biological materials such as tussahsilk fibroin [2], insect cuticular resilin [3, 4],the spore coat of Bacillus subtilis ( 5 ) ,and thefertilization membrane of the sea urchin egg [6] In all of these systems, dityrosine was detected by its characteristic natural fluorescence. The cross-links are believed to aid the mechanical stability of the biological structure involved Such a cross-linking reaction is observed in an in uitro system with horseradish peroxidase, as shown by Amadb et al [7] and Aeschbach et al [8]. In thepresent communication we report on the identification of dityrosine as a prominenctomponent of the outermost layers of the ascospore wall of the yeast, Saccharomyces cereuisiae
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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.
