title: Purification and structural characterisation of phospholipase A1 (Vespapase, Ves a 1) from Thai banded tiger wasp (Vespa affinis) venom.
abstract: The Thai banded tiger wasp (Vespa affinis) is one of the most dangerous vespid species in Southeast Asia, and stinging accidents involving this species still cause fatalities. In the present study, four forms of V. affinis phospholipase A(1) were identified through a proteomics approach. Two of these enzymes were purified by reverse-phase chromatography, and their biochemical properties were characterised. These enzymes, designated Ves a 1s, are not glycoproteins and exist as 33441.5 and 33474.4 Da proteins, which corresponded with the 34-kDa band observed via SDS-PAGE. The thermal stabilities of these enzymes were stronger than snake venom. Using an in vivo assay, no difference was found in the toxicities of the different isoforms. Furthermore, the toxicity of these enzymes does not appear to be correlated with their PLA(1) activity. The cDNAs of the full-length version of Ves a 1s revealed that the Ves a 1 gene consists of a 1005-bp ORF, which encodes 334 amino acid residues, and 67- and 227-bp 5' and 3' UTRs, respectively. The two isoforms are different by three nucleotide substitutions, resulting in the replacement of two amino acids. Through sequence alignment, these enzymes were classified as members of the pancreatic lipase family. The structural modelling of Ves a 1 used the rat pancreatic lipase-related protein 2 (1bu8A) as a template because it has PLA(1) activity, which demonstrated that this enzyme belongs to the α/β hydrolase fold family. The Ves a 1 structure, which is composed of seven α-helixes and eleven β-strands, contains the β-strand/ɛSer/α-helix structural motif, which contains the Gly-X-Ser-X-Gly consensus sequence. The typical surface structures that play important roles in substrate selectivity (the lid domain and the β9 loop) were shortened in the Ves a 1 structure, which suggests that this enzyme may only exhibit phospholipase activity. Moreover, the observed insertion of proline into the lid domain of the Ves a 1 structure is rare. We therefore propose that this proline residue might be involved in the stability and activity of Ves a 1s.
authors.affiliation: Protein and Proteomics Research Group, Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Sophida
authors.initials: S
authors.lastname: Sukprasert
authors.forename: Prapenpuksiri
authors.initials: P
authors.lastname: Rungsa
authors.forename: Nunthawun
authors.initials: N
authors.lastname: Uawonggul
authors.forename: Paroonkorn
authors.initials: P
authors.lastname: Incamnoi
authors.forename: Sompong
authors.initials: S
authors.lastname: Thammasirirak
authors.forename: Jureerut
authors.initials: J
authors.lastname: Daduang
authors.forename: Sakda
authors.initials: S
authors.lastname: Daduang
mesh_terms: D000818:Animals; D001483:Base Sequence; D002851:Chromatography, High Pressure Liquid; D018076:DNA, Complementary / Q000235:genetics; D016208:Databases, Factual; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D006135:Gryllidae; D007527:Isoenzymes / Q000737:chemistry; D013058:Mass Spectrometry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010243:Paralysis / Q000139:chemically induced; D054466:Phospholipases A1 / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013785:Thailand; D014862:Wasp Venoms / Q000737:chemistry / Q000201:enzymology*; D014863:Wasps / Q000737:chemistry*
chemical_list: D018076:DNA, Complementary; D007527:Isoenzymes; D014862:Wasp Venoms; D054466:Phospholipases A1; C581457:vespapase, Vespa affinis