Mussel glue protein has an open conformation.
Both native glue protein from marine mussels and a synthetic nonhydroxylated analog were analyzed by far-uv CD under a variety of conditions. Analysis of the CD spectra using various models strongly suggest a primarily random coil structure for both forms of the protein, a fact also supported by the absence of spectral change for the glue protein upon dilution into 6 M guanidine hydrochloride. The nonhydroxylated analog, which consists of 20 repeats of the peptide sequence Ala-Lys-Pro-Ser-Tyr-Pro-Pro-Thr-Tyr-Lys, was further characterized by enzyme modification using mushroom tyrosinase. Enzymatic hydroxylation of tyrosines was found to be best fit by a model containing two rate constants, 5.6 (+/- 0.6) X 10(-3) and 7.2 (+/- 0.3) X 10(-2) min-1. At equilibrium, HPLC analysis of digests showed nearly 100% conversion of Tyr-9 and only 15 to 35% conversion of Tyr-5. The Chou and Fasman rules for predicting structure were applied to the repeat sequence listed above. The rules predict the absence of alpha helix and beta pleated sheets in the structure of this peptide. On the other hand, beta turns are predicted to be present with Tyr-5 being in the region of highest probability. These data suggest that the protein in solution has only a small amount of secondary structure.
Williams
T
T
College of Marine Studies, University of Delaware, Lewes 19958.
Marumo
K
K
Waite
J H
JH
Henkens
R W
RW
D000595:Amino Acid Sequence; D000818:Animals; D049872:Bivalvia; D002942:Circular Dichroism; D008969:Molecular Sequence Data; D014442:Monophenol Monooxygenase; D011506:Proteins / Q000302:isolation & purification
D011506:Proteins; C037403:adhesive protein, mussel; D014442:Monophenol Monooxygenase