The American lobster, Homarus americanus, is a valuable economic species in the coastal Northeast. However, anthropogenic challenges have been implicated as physiological stressors capable of impairing its immune response. Given its economic importance, future anthropogenic challenges, and the current lack of information regarding molecules responsible for immune response, it is important to identify the biological components driving lobster immune response. The production and secretion of soluble antimicrobial peptides (AMPs) are important elements of the immune defense system. To date, relatively few antimicrobial compounds have been fully characterized from the lobster. In this study, we report on the detection and characterization of multiple crustin-like peptides, all with six disulfide bonds, extracted from H. americanus hemocytes. The mass of the mature, intact peptides was determine by nanoESI-LC/MS analysis. The number of disulfide bonds was established by mass shifts observed for the LC/MS analysis of reduced and alkylated samples. Top-down analysis of the reduced and alkylated samples was used to establish sequence tags. Bottom-up analysis was applied to hemocyte digests, with data searched against recently generated transcriptomes for lobster eyestalk and brain tissues. Cumulatively, this work has resulted in the detection of novel AMPs in the lobster and the structural characterization of post-translational modifications (pyroglutamate formation; amidation) of the mature peptides. This work sets the stage to better understand the role of these putative antimicrobial peptides in crustacean immune response.

Crustin and related putative antimicrobial peptides in the lobster, Homarus americanus: Identification using transcriptomics with top-down and bottom-up peptidomic strategies

255th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.