Background: In this paper, we describe cDNA cloning of a new anionic trypsin and a collagenolytic serine protease from king crab Paralithodes camtschaticus and the elucidation of their primary structures. Constructing the phylogenetic tree of these enzymes was undertaken in order to prove the evolutionary relationship between them.
Results: The mature trypsin PC and collagenolytic protease PC contain 237 (Mcalc 24.8 kDa) and 226 amino acid residues (Mcalc 23.5 kDa), respectively. Alignments of their amino acid sequences revealed a high degree of the trypsin PC identity to the trypsin from Penaeus vannamei (approximately 70%) and of the collagenolytic protease PC identity to the collagenase from fiddler crab Uca pugilator (76%). The phylogenetic tree of these enzymes was constructed.
Conclusions: Primary structures of the two mature enzymes from P. camtschaticus were obtained and compared with those of other proteolytic proteins, including some enzymes from brachyurans. A phylogenetic analysis was also carried out. These comparisons revealed that brachyurins are closely related to their vertebrate and bacterial congeners, occupy an intermediate position between them, and their study significantly contributes to the understanding of the evolution and function of serine proteases.