Molecular basis for the action of the collagen-specific chaperone Hsp47/SERPINH1 and its structure-specific client recognition.

Collagen is the most abundant protein in animals and is a major component of the extracellular matrix in tissues such as skin and bone. A distinctive structural feature of all collagen types is a unique triple-helical structure formed by tandem repeats of the consensus sequence Xaa-Yaa-Gly, in which Xaa and Yaa frequently are proline and hydroxyproline, respectively. Hsp47/SERPINH1 is a procollagen-specific molecular chaperone that, unlike other chaperones, specifically recognizes the folded conformation of its client. Reduced functional levels of Hsp47 were reported in severe recessive forms of osteogenesis imperfecta, and homozygous knockout is lethal in mice. Here we present crystal structures of Hsp47 in its free form and in complex with homotrimeric synthetic collagen model peptides, each comprising one Hsp47-binding site represented by an arginine at the Yaa-position of a Xaa-Yaa-Gly triplet. Two of these three binding sites in the triple helix are occupied by Hsp47 molecules, which bind in a head-to-head fashion, thus making extensive contacts with the leading and trailing strands of the collagen triple helix. The important arginine residue within the Xaa-Arg-Gly triplet is recognized by a conserved aspartic acid. The structures explain the stabilization of the triple helix as well as the inhibition of collagen-bundle formation by Hsp47. In addition, we propose a pH-dependent substrate release mechanism based on a cluster of histidine residues.

Methodological approaches and competence areas of nursing students in virtual reality simulation research - A scoping review.

OBJECTIVES: To analyze methodological approaches (theoretical frameworks, study designs, methods) and competence areas of nursing students in research on virtual reality simulations (VRS) with a high level of immersion. METHODS: A scoping review was performed. A systematic search of the literature was conducted on MEDLINE, CINAHL and ERIC databases on 30/11/22. In addition, a manual search was utilized. The extracted data relating to the research questions was descriptively analyzed and results were narratively summarized. RESULTS: In total 23 studies were included in the review. Selected studies employed a wide range of theoretical frameworks and research designs. The studies aimed to develop competences both through complex interventions where team-based skills are required in acute situations, and they described basic nursing interventions where individual skills are required in non-acute nursing care. CONCLUSIONS: A significant amount of the selected studies did not utilize a learning theory or an instructional design framework as a basis for their research. More knowledge was found on training specific skills compared to facilitating the attitudes and values of the participants. Therefore, there is a need for further research on whether nursing students' attitudes and values can be supported through VRS with a high level of immersion.

Structural and biochemical characterization of native and recombinant single insulin-like growth factor-binding domain protein (SIBD-1) from the Central American hunting spider Cupiennius salei (Ctenidae).

Cupiennius salei single insulin-like growth factor binding domain protein (SIBD-1) is an 8.6 kDa Cys-, Pro-, and Gly-rich protein, discovered in the hemocytes of the Central American hunting spider Cupiennius salei. SIBD-1 exhibits high sequence similarity to the N-terminal domain of the insulin-like growth factor-binding protein superfamily and has been reported to play an important role in the spider's immune system. Here, the recombinant expression and the elucidation of the three-dimensional structure of recombinant SIBD-1 and the characterization of the sugar moiety at Thr2 of native SIBD-1 is described in detail.