The Glu residue in the conserved ASN-Glu-Pro sequence of two highly divergent endo-β-1,4-glucanases is essential for enzymatic activity
| Autor: | David A. Johnson, Stephen Baird, Wing L. Sung, Verner L. Seligy, Makoto Yaguchi, Mary Alice Hefford |
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| Rok vydání: | 1990 |
| Předmět: |
DNA Mutational Analysis
Molecular Sequence Data Biophysics Bacillus Bacillus subtilis Biochemistry Conserved sequence Structure-Activity Relationship chemistry.chemical_compound Cellulase Glutamates Amino Acid Sequence Site-directed mutagenesis Molecular Biology chemistry.chemical_classification Binding Sites biology Mutagenesis Cell Biology biology.organism_classification Amino acid Glutamine Enzyme chemistry Lysozyme |
| Zdroj: | Biochemical and Biophysical Research Communications. 169:1035-1039 |
| ISSN: | 0006-291X |
| DOI: | 10.1016/0006-291x(90)91998-8 |
| Popis: | We initially aligned 28 different cellulase sequences in pairwise fashion and found half of them have the sequence -Asn-Glu-Pro- located in a region flanked by hydrophobic-rich amino acids. Based on lysozyme as a model, the glutamate residue could be essential for enzyme function. We tested this possibility by site-directed mutagenesis of the genes coding Bacillus polymyxa and Bacillus subtilis endo-beta-1,4-glucanases. The genes and amino acid sequences of these two enzymes show very little similarity. Change of Glu-194 and Glu-169 to the isosteric glutamine form in these respective enzymes resulted in a dramatic loss of CMCase activity which could be restored by reverse mutation. Similar mutations to less-conserved residues, Glu-72 and Glu-147, of the B. subtilis enzyme did not cause any loss of activity. |
| Databáze: | OpenAIRE |
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