title: Functional analysis of Pacific oyster (Crassostrea gigas) β-thymosin: Focus on antimicrobial activity.
abstract: An antimicrobial peptide, ∼5 kDa in size, was isolated and purified in its active form from the mantle of the Pacific oyster Crassostrea gigas by C18 reversed-phase high-performance liquid chromatography. Matrix-assisted laser desorption ionisation time-of-flight analysis revealed 4656.4 Da of the purified and unreduced peptide. A comparison of the N-terminal amino acid sequence of oyster antimicrobial peptide with deduced amino acid sequences in our local expressed sequence tag (EST) database of C. gigas (unpublished data) revealed that the oyster antimicrobial peptide sequence entirely matched the deduced amino acid sequence of an EST clone (HM-8_A04), which was highly homologous with the β-thymosin of other species. The cDNA possessed a 126-bp open reading frame that encoded a protein of 41 amino acids. To confirm the antimicrobial activity of C. gigas β-thymosin, we overexpressed a recombinant β-thymosin (rcgTβ) using a pET22 expression plasmid in an Escherichia coli system. The antimicrobial activity of rcgTβ was evaluated and demonstrated using a bacterial growth inhibition test in both liquid and solid cultures.
authors.affiliation: Biotechnology Research Division, National Fisheries Research and Development Institute, Busan 619-902, Republic of Korea. Electronic address: nambohye@korea.kr.
authors.forename: Bo-Hye
authors.initials: BH
authors.lastname: Nam
authors.affiliation: Department of Food Science and Biotechnology, Kunsan National University, Kunsan 573-701, Republic of Korea.
authors.forename: Jung-Kil
authors.initials: JK
authors.lastname: Seo
authors.affiliation: Department of Biotechnology, Pukyoung National University, Busan 608-737, Republic of Korea.
authors.forename: Min Jeong
authors.initials: MJ
authors.lastname: Lee
authors.affiliation: Biotechnology Research Division, National Fisheries Research and Development Institute, Busan 619-902, Republic of Korea.
authors.forename: Young-Ok
authors.initials: YO
authors.lastname: Kim
authors.affiliation: Biotechnology Research Division, National Fisheries Research and Development Institute, Busan 619-902, Republic of Korea.
authors.forename: Dong-Gyun
authors.initials: DG
authors.lastname: Kim
authors.affiliation: Biotechnology Research Division, National Fisheries Research and Development Institute, Busan 619-902, Republic of Korea.
authors.forename: Cheul Min
authors.initials: CM
authors.lastname: An
authors.affiliation: Department of Biotechnology, Pukyoung National University, Busan 608-737, Republic of Korea. Electronic address: ngpark@pknu.ac.kr.
authors.forename: Nam Gyu
authors.initials: NG
authors.lastname: Park
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D001412:Bacillus subtilis / Q000187:drug effects; D001483:Base Sequence; D002176:Candida albicans / Q000187:drug effects; D003001:Cloning, Molecular; D049896:Crassostrea / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology*; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000187:drug effects; D020224:Expressed Sequence Tags; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D013947:Thymosin / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
chemical_list: D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; D018076:DNA, Complementary; D012333:RNA, Messenger; D013947:Thymosin
keywords: Antimicrobial activity; Pacific oyster (Crassostrea gigas); Recombinant protein; Thymosin