Identification of a conserved N-terminal domain in the first module of ACV synthetases

Abstract The l‐δ‐(α‐aminoadipoyl)‐l‐cysteinyl‐d‐valine synthetase (ACVS) is a trimodular nonribosomal peptide synthetase (NRPS) that provides the peptide precursor for the synthesis of β‐lactams. The enzyme has been extensively characterized in terms of tripeptide formation and substrate specificity. The first module is highly specific and is the only NRPS unit known to recruit and activate the substrate l‐α‐aminoadipic acid, which is coupled to the α‐amino group of l‐cysteine through an unusual peptide bond, involving its δ‐carboxyl group. Here we carried out an in‐depth investigation on the architecture of the first module of the ACVS enzymes from the fungus Penicillium rubens and the bacterium Nocardia lactamdurans. Bioinformatic analyses revealed the presence of a previously unidentified domain at the N‐terminus which is structurally related to condensation domains, but smaller in size. Deletion variants of both enzymes were generated to investigate the potential impact on penicillin biosynthesis in vivo and in vitro. The data indicate that the N‐terminal domain is important for catalysis

Cleaning the Cellular Factory:Deletion of McrA in Aspergillus oryzae NSAR1 and the generation of a novel kojic acid deficient strain for cleaner heterologous production of secondary metabolites

The use of filamentous fungi as cellular factories, where natural product pathways can be refactored and expressed in a host strain, continues to aid the field of natural product discovery. Much work has been done to develop host strains which are genetically tractable, and for which there are multiple selectable markers and controllable expression systems. To fully exploit these strains, it is beneficial to understand their natural metabolic capabilities, as such knowledge can rule out host metabolites from analysis of transgenic lines and highlight any potential interplay between endogenous and exogenous pathways. Additionally, once identified, the deletion of secondary metabolite pathways from host strains can simplify the detection and purification of heterologous compounds. To this end, secondary metabolite production in Aspergillus oryzae strain NSAR1 has been investigated via the deletion of the newly discovered negative regulator of secondary metabolism, mcrA (multicluster regulator A). In all ascomycetes previously studied mcrA deletion led to an increase in secondary metabolite production. Surprisingly, the only detectable phenotypic change in NSAR1 was a doubling in the yields of kojic acid, with no novel secondary metabolites produced. This supports the previous claim that secondary metabolite production has been repressed in A. oryzae and demonstrates that such repression is not McrA-mediated. Strain NSAR1 was then modified by employing CRISPR-Cas9 technology to disrupt the production of kojic acid, generating the novel strain NSARΔK, which combines the various beneficial traits of NSAR1 with a uniquely clean secondary metabolite background

TRY plant trait database – enhanced coverage and open access

Plant traits - the morphological, anatomical, physiological, biochemical and phenological characteristics of plants - determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits - almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives