Publications by authors named "Helen Thorbjornsrud"
Article Synopsis
- The enzyme MtCM has low activity on its own but can increase its catalytic efficiency over 100 times when it forms a complex with a partner enzyme.
- Recently, scientists created an active variant of MtCM through directed evolution, but the crystal structure used for analysis posed challenges for understanding its function.
- Through molecular dynamics simulations and further experiments, researchers identified key interactions in MtCM that enhance its activity, particularly emphasizing the involvement of conserved residues like Pro52 and Asp55 in stabilizing the enzyme's active site.
Chorismate mutase (CM), an essential enzyme at the branch-point of the shikimate pathway, is required for the biosynthesis of phenylalanine and tyrosine in bacteria, archaea, plants, and fungi. MtCM, the CM from Mycobacterium tuberculosis, has less than 1% of the catalytic efficiency of a typical natural CM and requires complex formation with 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase for high activity. To explore the full potential of MtCM for catalyzing its native reaction, we applied diverse iterative cycles of mutagenesis and selection, thereby raising k/K 270-fold to 5 × 10ms, which is even higher than for the complex.
View Article and Find Full Text PDFFactor inhibiting hypoxia-inducible factor (FIH) is a 2-oxoglutarate-dependent protein hydroxylase that catalyses C3 hydroxylations of protein residues. We report FIH can accept (D)- and (L)-residues for hydroxylation. The substrate selectivity of FIH differs for (D) and (L) epimers, e.
View Article and Find Full Text PDFArticle Synopsis
- - Corynebacterium glutamicum is important for making amino acids, nucleotides, and vitamins, and it relies on the shikimate pathway enzymes DAHP synthase (CgDS) and chorismate mutase (CgCM) for producing aromatic compounds.
- - The study found that CgCM needs to form a complex with CgDS to work properly, and both enzymes are regulated by aromatic amino acids; amino acids like phenylalanine and tyrosine inhibit CgCM, while tryptophan activates it.
- - Detailed crystal structures of CgCM, CgDS, and their complex revealed how these interactions occur on a molecular level, showing that DAHP synthase plays a crucial role