Abstract
The CS-αβ architecture is a structural scaffold shared by a high number of small, cationic, cysteine-rich defense peptides, found in nearly all the major branches of the tree of life. Although several CS-αβ peptides involved in innate immune response have been described so far in bivalve mollusks, a clear-cut definition of their molecular diversity is still lacking, leaving the evolutionary relationship among defensins, mytilins, myticins and other structurally similar antimicrobial peptides still unclear. In this study, we performed a comprehensive bioinformatic screening of the genomes and transcriptomes available for marine mussels (Mytilida), redefining the distribution of mytilin-like CS-αβ peptides, which in spite of limited primary sequence similarity maintain in all cases a well-conserved backbone, stabilized by four disulfide bonds. Variations in the size of the alpha-helix and the two antiparallel beta strand region, as well as the positioning of the cysteine residues involved in the formation of the C1–C5 disulfide bond might allow a certain degree of structural flexibility, whose functional implications remain to be investigated. The identification of mytilins in Trichomya and Perna spp. revealed that many additional CS-αβ AMPs remain to be formally described and functionally characterized in Mytilidae, and suggest that a more robust scheme should be used for the future classification of such peptides with respect with their evolutionary origin.
Highlights
Antimicrobial peptides (AMPs) are fundamental effector molecules of the innate immune system, which are present in most living organisms, serving as a first line of defense against pathogens in the humoral immune response
Taxonomic Distribution of Mytilin-Like AMPs out that the phylogenetic relationship among Mytilidae are still a matter of debate and subject to iterative screening approach of all the data available for species pertaining to the change.The
This study reported for the first time the presence of mytilins outside the Mytilus Linnaeus
Summary
Antimicrobial peptides (AMPs) are fundamental effector molecules of the innate immune system, which are present in most living organisms, serving as a first line of defense against pathogens in the humoral immune response. Some filter-feeding aquatic organisms, such as bivalve mollusks, seem to have developed a remarkably rich arsenal of AMPs and other defense peptides, which might be interpreted as a strategy to efficiently manage bacterial infections from opportunist pathogens found in the water column [1]. The history of AMP research in mollusks has been always linked with marine mussels (Mytilus spp.), starting from the identification of several short cysteine-rich peptides from active hemolymph fractions of Mytilus galloprovincialis and Mytilus edulis in the mid-90s [2,3]. Reports revealed that most mussel AMPs are produced as inactive precursors and stored in granules within hemocytes, the main
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 call
