The fibronectin-binding domain of transglutaminase.
Guinea pig liver transglutaminase (EC 2.3.2.13) displays a Ca(2+)-independent binding (Ka = 10(7) M-1) to the same gelatin-binding domain of human plasma fibronectin that is known to form a very tight complex with the human red cell enzyme. The fibronectin-combining site of the liver transglutaminase was investigated by testing fragments obtained from the parent protein by controlled digestion with endoproteinase Lys-C. Overlay assays, probed with anti-fibronectin antibody, revealed that the fibronectin binding ability of the transglutaminase was encoded in a linear sequence in its 28-kDa N-terminal domain. Removal of the first 7 residues by further digestion of the purified 28-kDa material with endoproteinase Glu-C generated a 27-kDa fragment that, however, showed no binding activity. Thus, residues 1-7 in the liver enzyme seem to be of particular importance for influencing its ability to bind to fibronectin.
Jeong
J M
JM
Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611.
Murthy
S N
SN
Radek
J T
JT
Lorand
L
L
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002848:Chromatography, DEAE-Cellulose; D004591:Electrophoresis, Polyacrylamide Gel; D005353:Fibronectins / Q000378:metabolism*; D005454:Fluorescence Polarization; D006168:Guinea Pigs; D006801:Humans; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid; D011503:Transglutaminases / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*
D005353:Fibronectins; D010446:Peptide Fragments; D011503:Transglutaminases