Comparative analysis of two biliproteins, BP1 and BP2, from haemolymph of cabbage white butterfly, Pieris rapae.
Two blue-pigment binding proteins, BP1 and BP2, are present in larval and pupal haemolymph of cabbage white butterfly, Pieris rapae, and fluctuate in expression during development. Both BP1 and BP2 are found in pupal haemolymph in varying proportions as well as in adult haemolymph, while only small amounts of BP2 are found in larval haemolymph. BPs are separated by 75% ammonium sulfate, and then purified effectively by ion exchange column chromatography and preparative gel electrophoresis. It was shown that BP1 and BP2 have molecular masses of 20,244 and 19,878 Da, and isoelectric points of 7.0 and 6.8, respectively. Considering their amino acid compositions and N-terminal amino acid sequences, the two proteins are almost identical except the first N-terminal amino acid. The first amino acid of BP1 is asparagine, whereas the initial residue of BP2 is aspartic acid. Anti-BP1 cross-reacts with BP2, indicating that they have immunological homogeneity. Western blotting analyses revealed that only BP1 was present in the larval tissues such as fat body, integument, muscle, and hindgut. However, BP1 was not found in midgut, Malphigian tubules, and silk gland. BP1 was also present in the protein bodies, and both cuticle and hemocoel sides of larval epidermis cells by the transmission electron microscopic observation. The information in this report will facilitate studies on the molecular biology and biological significance of insect BPs.
Choi
Chi Won
CW
Department of Biology, Daejeon University, Daejeon, Korea.
Nam
Kyung-Pil
KP
Seo
Dong Hwan
DH
Choi
Jong Woon
JW
Lee
Chang Seok
CS
Kim
Hak Ryul
HR
Yun
Chi-Young
CY
D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D002080:Butterflies / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D006458:Hemolymph / Q000378:metabolism; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D007526:Isoelectric Point; D008297:Male; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016415:Sequence Alignment; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D019476:Insect Proteins