By a recombinant DNA approach we have prepared Escherichia coli cytoplasmic membranes that are highly enriched in the terminal electron transfer enzyme fumarate reductase. This enzyme is composed of four nonidentical subunits in equal molar ratio. A 69,000-dalton covalent flavin-containing subunit a
A Structural Model of the Membrane-Bound Aromatic Prenyltransferase UbiA from E. coli
✍ Scribed by Lars Bräuer; Wolfgang Brandt; Diana Schulze; Svetlana Zakharova; Ludger Wessjohann
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 743 KB
- Volume
- 9
- Category
- Article
- ISSN
- 1439-4227
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
The membrane‐bound enzyme 4‐hydroxybenzoic acid oligoprenyltransferase (ubiA) from E. coli is crucial for the production of ubiquinone, the essential electron carrier in prokaryotic and eukaryotic organisms. On the basis of previous modeling analyses, amino acids identified as important in two putative active sites (1 and 2) were selectively mutated. All mutants but one lost their ability to form geranylated hydroxybenzoate, irrespective of their being from active site 1 or 2. This suggests either that the two active sites are interrelated or that they are in fact only one site. With the aid of the experimental results and a new structure‐based classification of prenylating enzymes, a relevant 3D model could be developed by threading. The new model explains the substrate specificities and is in complete agreement with the results of site‐directed mutagenesis. The high similarity of the active fold of UbiA‐transferase to that of 5‐epi‐aristolochene synthase (Nicotiana tabacum), despite a low homology, allows a hypothesis on a convergent evolution of these enzymes to be formed.
📜 SIMILAR VOLUMES
Two distinct forms of the 06 antigen (LPS) from E. coli were analysed using 'H and 13C NMR spectroseopoy. Their structures were found to be + 4)-P-D-Mang-( 1 + ~)-LY-D-G~c~NAc-( 1 + 4)-cy-p-GalpNAc-( 1 + 3)-p-~-Manp -( 1 + : X In the 06-specific polysaccharide from E. coli 06 : K2 and 06 : K13, X i
Coumarin antibiotics, such as clorobiocin, novobiocin, and coumermycin A1, inhibit the supercoiling activity of gyrase by binding to the gyrase B (GyrB) subunit. Previous crystallographic studies of a 24-kDa Nterminal domain of GyrB from E. coli complexed with novobiocin and a cyclothialidine analog
## Abstract In the modeled structure of the Klenow fragment of __E. coli__ DNA polymerase I, we have identified a distinct region that exhibits a strong electropositive potential contour. The examination of the distribution of the electropositive and negative potential across the two‐dimensional sl