Role of tyrosine residues on structure-function of fructose-1,6-biphosphate aldolase from Ceratitis capitata.
Tyrosine contributions to the structure-function relationship in the fructose-1, 6-biphospate aldolase from C. capitata have been investigated. There are three well defined groups of tyrosine residues with different roles in the structure of the insect aldolase. C-terminal tyrosine residues are essential for the maintenance of the catalytic conformation. Releasing of these residues by carboxypeptidase A treatment results in complex conformational changes according to CD studies. Another tyrosine residue group is located at the active site, and the substrate, fructose-1, 6-biphosphate, protects it upon nitration. Chemical modification of this residue results in enzyme activity changes similar to those induced by carboxypeptidase digestion. Enzyme-substrate interaction results in a change of the microenvironment of at least three tyrosine residues per subunit with different accessibility for tetranitromethane.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002268:Carboxypeptidases / Q000378:metabolism; D043422:Carboxypeptidases A; D002942:Circular Dichroism; D004175:Diptera / Q000201:enzymology*; D005634:Fructose-Bisphosphate Aldolase / Q000378:metabolism*; D007700:Kinetics; D011487:Protein Conformation; D013774:Tetranitromethane / Q000494:pharmacology; D014443:Tyrosine
D000596:Amino Acids; D014443:Tyrosine; D002268:Carboxypeptidases; D043422:Carboxypeptidases A; D005634:Fructose-Bisphosphate Aldolase; D013774:Tetranitromethane