title: Molecular cloning and characterization of a venom phospholipase A2 from the bumblebee Bombus ignitus.
abstract: Phospholipase A(2) (PLA(2)) is one of the main components of bee venom. Here, we identify a venom PLA(2) from the bumblebee, Bombus ignitus. Bumblebee venom PLA(2) (Bi-PLA(2)) cDNA, which was identified by searching B. ignitus venom gland expressed sequence tags, encodes a 180 amino acid protein. Comparison of the genomic sequence with the cDNA sequence revealed the presence of four exons and three introns in the Bi-PLA(2) gene. Bi-PLA(2) is an 18-kDa glycoprotein. It is expressed in the venom gland, cleaved between the residues Arg44 and Ile45, and then stored in the venom sac. Comparative analysis revealed that the mature Bi-PLA(2) (136 amino acids) possesses features consistent with other bee PLA(2)s, including ten conserved cysteine residues, as well as a highly conserved Ca(2+)-binding site and active site. Phylogenetic analysis of bee PLA(2)s separated the bumblebee and honeybee PLA(2) proteins into two groups. The mature Bi-PLA(2) purified from the venom of B. ignitus worker bees hydrolyzed DBPC, a known substrate of PLA(2). Immunofluorescence staining of Bi-PLA(2)-treated insect Sf9 cells revealed that Bi-PLA(2) binds at the cell membrane and induces apoptotic cell death.
authors.affiliation: College of Natural Resources and Life Science, Dong-A University, Busan 604-714, Republic of Korea.
authors.forename: Yu
authors.initials: Y
authors.lastname: Xin
authors.forename: Young Moo
authors.initials: YM
authors.lastname: Choo
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Hu
authors.forename: Kwang Sik
authors.initials: KS
authors.lastname: Lee
authors.forename: Hyung Joo
authors.initials: HJ
authors.lastname: Yoon
authors.forename: Zheng
authors.initials: Z
authors.lastname: Cui
authors.forename: Hung Dae
authors.initials: HD
authors.lastname: Sohn
authors.forename: Byung Rae
authors.initials: BR
authors.lastname: Jin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001514:Bee Venoms / Q000201:enzymology*; D001516:Bees; D003001:Cloning, Molecular; D015971:Gene Expression Regulation, Enzymologic; D008969:Molecular Sequence Data; D054467:Phospholipases A2 / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D010802:Phylogeny; D017422:Sequence Analysis, DNA
chemical_list: D001514:Bee Venoms; D054467:Phospholipases A2