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Subunit communication in the tryptophan synthase α 2 β 2 complex Effects of β subunit ligands on proteolytic cleavage of a flexible loop in the α subunit
Author(s) -
Ruvinov Sergei B.,
Miles Edith Wilson
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)80246-d
Subject(s) - protein subunit , cleavage (geology) , chemistry , tryptophan synthase , atp synthase , proteolysis , loop (graph theory) , biophysics , biochemistry , stereochemistry , tryptophan , enzyme , biology , amino acid , gene , paleontology , fracture (geology) , mathematics , combinatorics
To probe the structural basis for ligand‐mediated communication between the α and β subunits in the tryptophan synthase α 2 β 2 complex, we have determined the effects of ligands of the α and β subunits on proteolysis of a flexible loop in the α subunit. We find that addition of a ligand of the β subunit ( l ‐serine, d ‐tryptophan, or l ‐tryptophan) in combination with a ligand of the α subunit (α‐glycerol 3‐phosphate) almost completely prevents the tryptic cleavage of the α subunit loop. Thus, the binding of a ligand to the β‐site affects the conformation of the α subunit 25–30 Å distant.