title: Identification and activity of a lower eukaryotic serine proteinase inhibitor (serpin) from Cyanea capillata: analysis of a jellyfish serpin, jellypin.
abstract: Delineating the phylogenetic relationships among members of a protein family can provide a high degree of insight into the evolution of domain structure and function relationships. To identify an early metazoan member of the high molecular weight serine proteinase inhibitor (serpin) superfamily, we initiated a cDNA library screen of the cnidarian, Cyanea capillata. We identified one serpin cDNA encoding for a full-length serpin, jellypin. Phylogenetic analysis using the deduced amino acid sequence showed that jellypin was most similar to the platyhelminthe Echinococcus multiocularis serpin and the clade P serpins, suggesting that this serpin evolved approximately 1000 million years ago (MYA). Modeling of jellypin showed that it contained all the functional elements of an inhibitory serpin. In vitro biochemical analysis confirmed that jellypin was an inhibitor of the S1 clan SA family of serine proteinases. Analysis of the interactions between the human serine proteinases, chymotrypsin, cathepsin G, and elastase, showed that jellypin inhibited these enzymes in the classical serpin manner, forming a SDS stable enzyme/inhibitor complex. These data suggest that the coevolution of serpin structure and inhibitory function date back to at least early metazoan evolution, approximately 1000 MYA.
authors.affiliation: Department of Pediatrics, Harvard Medical School and Division of Newborn Medicine, Children's Hospital, 300 Longwood Avenue, Boston, Massachusetts 02115-5737, USA.
authors.forename: Elisabeth B
authors.initials: EB
authors.lastname: Cole
authors.forename: David
authors.initials: D
authors.lastname: Miller
authors.forename: David
authors.initials: D
authors.lastname: Rometo
authors.forename: Robert M
authors.initials: RM
authors.lastname: Greenberg
authors.forename: Dieter
authors.initials: D
authors.lastname: Brömme
authors.forename: Sule
authors.initials: S
authors.lastname: Cataltepe
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Pak
authors.forename: David R
authors.initials: DR
authors.lastname: Mills
authors.forename: Gary A
authors.initials: GA
authors.lastname: Silverman
authors.forename: Cliff J
authors.initials: CJ
authors.lastname: Luke
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D015723:Gene Library; D006801:Humans; D008969:Molecular Sequence Data; D010802:Phylogeny; D011489:Protein Denaturation; D037401:Scyphozoa / Q000201:enzymology* / Q000235:genetics*; D016415:Sequence Alignment; D015843:Serpins / Q000145:classification / Q000235:genetics / Q000378:metabolism*
chemical_list: D015843:Serpins