Sturm, S, Dowle, A, Audsley, N et al. (1 more author) (2021) Mass spectrometric characterisation of the major peptides of the male ejaculatory duct, including a glycopeptide with an unusual zwitterionic glycosylation. Journal of Proteomics, 246. 104307. ISSN 1874-3919
Abstract
Peptides present in the seminal fluid of Drosophila melanogaster can function as antimicrobial agents, enzyme inhibitors and as pheromones that elicit physiological and behavioural responses in the post-mated female. Understanding the molecular interactions by which these peptides influence reproduction requires detailed knowledge of their molecular structures. However, this information is often lacking and cannot be gleaned from just gene sequences and standard proteomic data. We now report the native structures of four seminal fluid peptides (andropin, CG42782, Met75C and Acp54A1) from the ejaculatory duct of male D. melanogaster. The mature CG42782, Met75C and Acp54A1 peptides each have a cyclic structure formed by a disulfide bond, which will reduce conformational freedom and enhance metabolic stability. In addition, the presence of a penultimate Pro in CG42782 and Met75C will help prevent degradation by carboxypeptidases. Met75C has undergone more extensive post-translational modifications with the formation of an N-terminal pyroglutamyl residue and the attachment of a mucin-like O-glycan to the side chain of Thr4. Both of these modifications are expected to further enhance the stability of the secreted peptide. The glycan has a rare zwitterionic structure comprising an O-linked N-acetyl hexosamine, a hexose and, unusually, phosphoethanolamine. A survey of various genomes showed that andropin, CG42782, and Acp54A1 are relatively recent genes and are restricted to the melanogaster subgroup. Met75C, however, was also found in members of the obscura species groups and in Scaptodrosophila lebanonensis. Andropin is related to the cecropin gene family and probably arose by tandem gene duplication, whereas CG42782, Met75C and Acp54A1 possibly emerged de novo. We speculate that the post-translational modifications that we report for these gene products will be important not only for a biological function, but also for metabolic stability and might also facilitate transport across tissue barriers, such as the blood-brain barrier of the female insect.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2021 Published by Elsevier B.V. This is an author produced version of an article published in Journal of Proteomics. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Seminal fluid peptides; Novel genes; Andropin; CG42782; Met75C; Acp54A1; Male accessory organs; Ejaculatory duct; Drosophila melanogaster; Glycopeptide; Phosphoethanolamine |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Biological Sciences (Leeds) > School of Biology (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 28 Jun 2021 08:46 |
Last Modified: | 28 Jun 2022 08:54 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.jprot.2021.104307 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:175554 |