Protein characterization and fatty acid composition of subfraction II of VHDL fraction of the spider Polybetes pythagoricus

LAINO A.; C.F. GARCIA; CUNNINGHAM MONICA

BIOCELL

INST HISTOL EMBRIOL-CONICET

Lugar: Mendoza; Año: 2015 vol. 39 p. 33 - 40

0327-9545

VHDL fraction contains hemocyanin as its major apoprotein; it transports most of the circulating lipids in the spider Polybetes pythagoricus (Holmberg 1875). This work shows that subfraction II (major component) of the hemolymphatic fraction is composed of a single protein of 420 kDa under native conditions and three subunits, 67, 105 and 121 kDa under denaturing conditions.Circular dichroism indicated that this subfraction contains 20% -helix, 29% β-sheet, 22.7% turns and 29.7% unordered structure. Trypsinolysis susceptibility comparison of proteins shows that the 105 and 121 KDa subunits are more susceptible indicating that proteins would be more exposed to the aqueous medium. Peptide mass fingerprinting of the 67 and 105 kDa subunits is shown. Subunit of 67 kDa is similar to subunit 3 of the spider Cupiennius salei hemocyanin (21% sequence). Concerning the 105kDa subunit, the sequence identity with a protein from the insect Anopheles gambiae (20% sequence) is also shown. N-terminal amino acid sequence from subunit of 121 kDa is determined. In relation to fatty acids, 16:0, 18:0, 18:1 and 18:2 are found to be majority. In summary an improvement in the understanding of subfraction II structure responsible for greater lipid transport in the spider P. pythagoricusis shown.