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Polysaccharides in plant cell walls serve as a rich carbon and energy source, yet their structural complexity presents a barrier to efficient degradation. To address this, anaerobic microorganisms like R. flavefaciens have developed sophisticated multi-enzyme complexes known as cellulosomes, which enable the efficient breakdown of these recalcitrant polysaccharides. These complexes are assembled through high-affinity interactions between cohesin (Coh) modules in scaffoldin proteins and dockerin (Doc) modules in cellulosomal enzymes. R. flavefaciens FD-1 harbors one of the most intricate cellulosomes described to date, comprising over 200 Doc-containing proteins encoded in its genome. Despite substantial research on this cellulosome, the role of a group of truncated but functional dockerins, known as group-2 Docs, remains unclear. In this study, we present a detailed structural and binding analysis of a Coh-Doc complex involving the cohesin from the cell-anchoring scaffoldin ScaE and a group-2 Doc that bears only one of the two Ca+2-coordinating loops that characterise the canonical Docs. Our findings reveal a novel tripartite binding mechanism, in which the cohesin can simultaneously bind two distinct dockerin units in three alternative conformations. This discovery provides new insights into the modular versatility of the R. flavefaciens cellulosome and sheds light on the mechanisms that enhance its efficiency in polysaccharide degradation.

The Upper Jurassic beds of the Lusitanian Basin in central Portugal yield diverse dinosaurian fauna, dated to the Kimmeridgian–Tithonian interval. Saurischian dinosaurs are, overall, more abundant than their ornithischian counterparts, in terms of both specimens collected and species recognized. Iguanodontians are so far represented by the styracosternan Draconyx loureiroi, the dryosaurid Eousdryosaurus nanohallucis and the enigmatic dryomorphan Hesperonyx martinhotomasorum. Here we aim to highlight the diversity of this clade in the Late Jurassic of Portugal, presenting evidence for yet another species of ankylopollexian iguanodontian dinosaur, represented by the specimen SHN.JJS.015, which is housed at the Sociedade de História Natural, Torres Vedras. Detailed comparisons rule out attribution to previously known taxa, and phylogenetic analyses that include SHN.JJS.015 indicate early-diverging ankylopollexian affinities for this specimen. As there is no robust diagnosis, we do not erect a new formal species for it at this stage. Nevertheless, this specimen represents a previously unreported taxon that highlights greater diversity than previously estimated among the iguanodontians of the Late Jurassic and highlights the importance of Europe in diversification and dispersal events of this clade. A series of smaller, isolated femora from the same sub-basin as SHN.JJS.015 may represent the same taxon, presenting evidence of thriving communities of ankylopollexians during the Kimmeridgian–Tithonian interval in Portugal.

The teacher’s central role in technology integration and the challenges of that integration emphasise the need for a deeper understanding about the teacher’s knowledge required to teach with technology. Based on previous work and a systematic literature review, we identified three knowledge models often used: TPACK, KTMT and
PTK. The goal of this paper is to discuss the similarities and differences between these knowledge models and present a Global Model. This Global Model is not a new model. On the contrary, it is a model developed based on the existing models and intending to integrate in a single model the knowledge domains considered in the different existing models. The Global Model highlights the common domains considered and the common roots for the three models, but it also makes explicit the differences, mostly related to the understanding of the domains or even to the domains considered, and also to the way how the knowledge’s development is conceived.