A 9.6 S protein is the third calcium-insoluble component of the sea urchin hyaline layer.
A third major, calcium-insoluble component of the sea urchin (Strongylocentrotus purpuratus) hyaline layer has been purified and physically characterized. In the absence of divalent cations, the native, soluble protein has a sedimentation coefficient of 9.6 S and a molecular weight of 4.5 +/- 0.1 x 10(5). These data indicate that this large protein assumes an elongated, nonspherical conformation in solution. Its sedimentation behavior and its mobility on nondenaturing electrophoretic gels distinguish the 9.6 S protein from the 11.6 S and 6.4 S hyalin proteins we have previously characterized. That the 6.4 S, 9.6 S, and 11.6 S proteins are the major calcium-insoluble structural components of the hyaline layer is supported by the fact that we have found them in a variety of hyalin protein fractions prepared by a number of standard approaches. All three proteins are precipitated by calcium ions, thus fitting the operational definition of hyalin. Evidence is presented that the 11.6 S protein may overlie the 9.6 S protein in the hyaline layer.
Justice
R W
RW
Department of Biology, University of California, Riverside 92521.
Nagel
G M
GM
Gottschling
C F
CF
Damis
M F
MF
Carroll
E J
EJ
D000818:Animals; D002118:Calcium; D002498:Centrifugation; D055598:Chemical Phenomena; D011232:Chemical Precipitation; D002627:Chemistry, Physical; D004591:Electrophoresis, Polyacrylamide Gel; D008970:Molecular Weight; D011506:Proteins / Q000032:analysis* / Q000737:chemistry; D012617:Sea Urchins / Q000196:embryology*
D011506:Proteins; D002118:Calcium