title: Molecular cloning and functional characterization of crustapain: a distinct cysteine proteinase with unique substrate specificity from northern shrimp Pandalus borealis.
abstract: A cDNA clone encoding a cysteine proteinase of the papain superfamily has been isolated from the hepatopancreas of northern shrimp Pandalus borealis (NsCys). NsCys shares the highest identity of 64% with a cathepsin L-like cysteine proteinase from lobster, and its identity to the well-characterized mammalian cathepsins S, L, and K falls within a narrow range of 54-59%. However, it differs from each of these cathepsins in certain key residues including, for example, the unique occurrence of tryptophan and cysteine residues at the structurally important S2 subsite. Consequently, NsCys produced in Pichia pastoris appears to be distinct in various physicokinetic properties. The recombinant enzyme is active and stable over a wide range of pH values, and its substrate specificity is unusual, as demonstrated by its poor affinity for phenylalanine residues. Instead, it shows the highest specificity for proline residues, a property similar to cathepsin K. Unlike cathepsin K, however, NsCys cleaves valine residues more efficiently than leucine. Similar results were obtained with the natural peptide substrate glucagon. The shrimp proteinase is further distinguished by its potent collagenolytic activity, resulting in a cleavage pattern reminiscent of bacterial collagenase. To distinguish such unique structural and enzymatic properties, we propose the trivial name "crustapain" for the shrimp proteinase, indicating that it is a papain-like cysteine proteinase from a crustacean species.
authors.affiliation: Laboratory of Aquatic Molecular Biology and Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Aoki
authors.forename: Md Nazmul
authors.initials: MN
authors.lastname: Ahsan
authors.forename: Shugo
authors.initials: S
authors.lastname: Watabe
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002403:Cathepsins / Q000737:chemistry; D003001:Cloning, Molecular; D003546:Cysteine Endopeptidases / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology*; D018076:DNA, Complementary; D015698:Genomic Library; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D008969:Molecular Sequence Data; D033542:Pandalidae; D010802:Phylogeny; D012333:RNA, Messenger / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
chemical_list: D018076:DNA, Complementary; D012333:RNA, Messenger; D011994:Recombinant Proteins; D002403:Cathepsins; D003546:Cysteine Endopeptidases