Characterisation of the Adhesive Proteins of a Major Fouling Organism, the Barnacle. Part 4
Rept. no. 4
ARMY NATICK RESEARCH DEVELOPMENT AND ENGINEERING CENTER MA
Pagination or Media Count:
The cement of B. eburneus can be dissolved and digested by using cyanogen bromide in 70 formic acid. By careful evaporation of the reagent the resulting proteins and peptides can be redissolved in SDS and analysed by SDS- PAGE. Many of the darkest staining proteins come from the digestion of a 36 kD adhesive protein AP. These bands are most easily semi-dry blotted from the gels onto polyvinylidene difluoride PVDF membranes from where they can be sequenced. Several other bands are not easily blotted and little data is available for these at the moment. Three fragments of the 36 kD protein have been sequenced the N-terminus of the 36 kD protein NH2-TYYPY LKTRH FGGID LTRY F5 which by amino acid analysis is shown to be tyrosine-rich and two other fragments, F3 F2 respectively, with sequence NH2-LFPRL PLIVS KLRTY RFAP and NH2-NLV APRR VDFRP FYDRY. Comparing the amino acid analyses of these three fragments and one other for which we have no sequence shows that Fl is ASX-, SER- and LEU-rich, F5 is GLX-, PRO-, TYR-, CYS- and LEU-rich, F2 is SER-, GLY- and LEU-rich, and F3 is SER-, PRO- and LEU-rich. The high levels of LEU in all these peptides is reflected in the overall composition of the cement of B. eburneus showing that the majority of the cement is made of this 36 kD element. Two other fragments, F4 and F6, are not derived from the 36 kD protein and do not seem to be related to the previously analysed 55kD cement protein.