Single amino acid substitutions in one Ca2+ binding site of uvomorulin abolish the adhesive function.
We show that a synthetic peptide corresponding to the sequence of one putative Ca2+ binding motif of the cell adhesion molecule uvomorulin is able to complex Ca2+. This function is abolished if the first Asp in the peptide is replaced by Lys. Accordingly, we expressed in L cells mutant uvomorulin with a replacement of Asp to Lys or Ala. Mutant protein was resistant to Ca2+/trypsin under mild conditions but became susceptible at or near the site of replacement at higher concentrations, leaving the remaining Ca2+ binding domains protected. Remarkably, in cell aggregation assays both mutant uvomorulins failed to mediate cell adhesiveness, demonstrating that a single amino acid substitution in one Ca2+ binding site inactivates the adhesive function.
Ozawa
M
M
Max-Planck Institut für Immunobiologie, Molekulare Embryologie, Freiburg, Federal Republic of Germany.
Engel
J
J
Kemler
R
R
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D015820:Cadherins / Q000235:genetics* / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002448:Cell Adhesion; D002449:Cell Aggregation; D002942:Circular Dichroism; D007700:Kinetics; D007739:L Cells / Q000166:cytology / Q000502:physiology; D051379:Mice; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D015345:Oligonucleotide Probes; D010455:Peptides / Q000138:chemical synthesis; D010957:Plasmids; D011485:Protein Binding; D011487:Protein Conformation; D015183:Restriction Mapping; D014162:Transfection
D015820:Cadherins; D015345:Oligonucleotide Probes; D010455:Peptides; D002118:Calcium