title: Cloning and isolation of a Conus cysteine-rich protein homologous to Tex31 but without proteolytic activity.
abstract: We cloned and isolated a cysteine-rich protein, designated Mr30, from Conus marmoreus. Mr30 belongs to the cysteine-rich secretory protein family that is highly homologous to Tex31 previously obtained from Conus textile and reported as a protease responsible for processing of pro-conotoxins. Mr30, purified by a procedure similar to that of Tex31, indeed showed low proteolytic activity. However, further investigations revealed that the detected protease activity actually resulted from a trace amount of protease(s) contamination rather than from Mr30 itself. This finding led us to rethink the role of conus cysteine-rich secretory proteins: they were probably not responsible for the processing of pro-conotoxins as previously deduced, but their real biological functions remained to be clarified.
authors.affiliation: Institute of Protein Research, Tongji University, Shanghai 200092, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Qian
authors.forename: Zhan-yun
authors.initials: ZY
authors.lastname: Guo
authors.forename: Cheng-wu
authors.initials: CW
authors.lastname: Chi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D020916:Conotoxins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D052078:Conus Snail / Q000235:genetics* / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D008969:Molecular Sequence Data; D010447:Peptide Hydrolases / Q000235:genetics / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D017386:Sequence Homology, Amino Acid
chemical_list: D020916:Conotoxins; C059360:Conus textile toxin; D017931:DNA Primers; D018076:DNA, Complementary; D010447:Peptide Hydrolases