The structure of apo tryptophanase from Escherichia coli reveals a wide-open conformation Journal Article
| Authors: | Tsesin, N.; Kogan, A.; Gdalevsky, G. Y.; Himanen, J. P.; Cohen-Luria, R.; Parola, A. H.; Goldgur, Y.; Almog, O. |
| Article Title: | The structure of apo tryptophanase from Escherichia coli reveals a wide-open conformation |
| Abstract: | The crystal structure of apo tryptophanase from Escherichia coli (space group F222, unit-cell parameters a = 118.4, b = 120.1, c = 171.2 Å) was determined at 1.9 Å resolution using the molecular-replacement method and refined to an R factor of 20.3% (R free = 23.2%). The structure revealed a significant shift in the relative orientation of the domains compared with both the holo form of Proteus vulgaris tryptophanase and with another crystal structure of apo E. coli tryptophanase, reflecting the internal flexibility of the molecule. Domain shifts were previously observed in tryptophanase and in the closely related enzyme tyrosine phenol-lyase, with the holo form found in an open conformation and the apo form in either an open or a closed conformation. Here, a wide-open conformation of the apo form of tryptophanase is reported. A conformational change is also observed in loop 297-303. The structure contains a hydrated Mg2+ at the cation-binding site and a Cl- ion at the subunit interface. The enzyme activity depends on the nature of the bound cation, with smaller ions serving as inhibitors. It is hypothesized that this effect arises from variations of the coordination geometry of the bound cation. © International Union of Crystallography 2007. |
| Keywords: | genetics; methodology; metabolism; enzymology; chemistry; escherichia coli; substrate specificity; binding site; models, molecular; crystallography, x-ray; protein structure, tertiary; binding sites; chemical structure; catalysis; protein secondary structure; crystallization; x ray crystallography; enzyme specificity; protein tertiary structure; protein structure, secondary; escherichia coli proteins; escherichia coli protein; plp-dependent enzymes; tryptophanase; proteus vulgaris |
| Journal Title: | Acta Crystallographica Section D: Biological Crystallography |
| Volume: | 63 |
| Issue: | 9 |
| ISSN: | 0907-4449 |
| Publisher: | Wiley Blackwell |
| Date Published: | 2007-08-17 |
| Start Page: | 969 |
| End Page: | 974 |
| Language: | English |
| DOI: | 10.1107/s0907444907036396 |
| PUBMED: | 17704565 |
| PROVIDER: | scopus |
| DOI/URL: | |
| Notes: | --- - "Cited By (since 1996): 3" - "Export Date: 17 November 2011" - "CODEN: ABCRE" - "Source: Scopus" |
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