Identification and bioinformatics analysis of a novel member of the lumbrokinase gene family in earthworms

<h4>Background</h4>Lumbrokinase is a novel antithrombotic drug isolated and purified from earthworms and used in the treatment of stroke and cardiovascular disease. However, to date, there has been no systematic classification of lumbrokinase genes.<h4>Methods</h4>In this study, a new member of the lumbrokinase gene family <i>LUKA</i>, which has not yet been reported, was cloned from <i>Eisenia andrei</i> by a homologous sequence method. The full-length cDNA sequence of <i>LUKA</i> was obtained through second-generation sequencing. The gene and protein were analyzed using various bioinformatics software tools.<h4>Results</h4>The molecular formula of LUKA was C₁₃₄₇H₂₀₆₈N₃₆₀O₄₁₉S₁₈, indicating it is a stable protein. The amino acid sequence of LUKA contained high proportion of valine (10.2%) and serine (9.2%) and possessed a peptide signal along with the corresponding cleavage site.<h4>Conclusion</h4>Phylogenetic analysis showed that LUKA has multiple distinct amino acid sites compared with other lumbrokinases and represents a rare type of lumbrokinase. This study provides a new genetic material of rare lumbrokinase types.