Premium
The environments ofTrp‐248 and Trp‐330 in tryptophan indole‐lyase from Escherichia coli
Author(s) -
Phillips Robert S.,
Gollnick Paul
Publication year - 1990
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(90)81011-c
Subject(s) - indole test , tryptophan , escherichia coli , chemistry , tryptophanase , biochemistry , microbiology and biotechnology , biology , amino acid , gene
The two tryptophan residues, Trp‐248 and Trp‐330, in tryptophan indole‐lyase (tryptophanase) from E. coli have been separately mutated to phenylalanine using site‐directed mutagenesis. Both single tryptophan mutant enzymes have full catalytic activity, but exhibit different fluorescence and near‐UV circular dichroism spectra. These results indicate that Trp‐330 is more deeply buried than is Trp‐248, and is in a more asymmetric environment. Neither residue reacts with N ‐bromosuccinimide (NBS), although tryptophan indole‐lyase is inactivated by NBS. These results demonstrate that the tryptophan residues in tryptophan indole‐lyase are not catalytically essential.