Assembly of the sea urchin extraembryonic hyaline layer; Ca2+ and Mg2+ act independently and at different sites on the pathway leading to hyalin-gel formation.
We have studied the interactions of Ca2+ with the sea urchin extraembryonic coat protein hyalin. As reported previously, Ca2+ alone was ineffective in inducing hyalin-gel (large aggregate) formation. This reaction required the additional presence of Mg2+ and NaCl. However, the results of tryptic digestion and nondenaturing agarose gel electrophoresis experiments demonstrated that Ca2+ could induce hyalin self-association into small aggregates in the absence of Mg2+ and NaCl. Magnesium did not modulate the interactions of Ca2+ with hyalin. In addition, Mg2+ had minimal effects on the conformation of hyalin. These results have been incorporated into a model delineating the pathway leading to hyalin-gel formation.
Robinson
J J
JJ
Department of Biochemistry, Memorial University of Newfoundland, St. John's, Canada.
Brennan
C
C
D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology*; D005782:Gels; D007447:Invertebrate Hormones / Q000737:chemistry / Q000378:metabolism*; D046911:Macromolecular Substances; D008274:Magnesium / Q000494:pharmacology*; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D011487:Protein Conformation / Q000187:drug effects; D012617:Sea Urchins / Q000196:embryology*; D012965:Sodium Chloride / Q000494:pharmacology; D014357:Trypsin
D005782:Gels; D007447:Invertebrate Hormones; D046911:Macromolecular Substances; D008565:Membrane Proteins; D012965:Sodium Chloride; D014357:Trypsin; D008274:Magnesium; D002118:Calcium