A Variation of the DeLone and McLean Model for Collaborative Commerce Services: A Structural Equation Model

This study intends to provide theory-driven empirical findings of the factors affecting users’ loyalty to a collaborative commerce platform provider and further suggests that the platform loyalty lead to future extended use of collaborative commerce services. DeLone and McLean model serves as a basic framework for this study. Our variation of the model tested the impact of perceived value, relationship quality, and service quality on platform loyalty, which would influence future extended use of collaboration commerce services. Our results confirm that perceived value and platform quality were the best predictors for platform loyalty, which in turn, had a positive influence on future extended use intention

Crystal structure of Tpa1 from Saccharomyces cerevisiae, a component of the messenger ribonucleoprotein complex

Tpa1 (for termination and polyadenylation) from Saccharomyces cerevisiae is a component of a messenger ribonucleoprotein (mRNP) complex at the 3′ untranslated region of mRNAs. It comprises an N-terminal Fe(II)- and 2-oxoglutarate (2OG) dependent dioxygenase domain and a C-terminal domain. The N-terminal dioxygenase domain of a homologous Ofd1 protein from Schizosaccharomyces pombe was proposed to serve as an oxygen sensor that regulates the activity of the C-terminal degradation domain. Members of the Tpa1 family are also present in higher eukaryotes including humans. Here we report the crystal structure of S. cerevisiae Tpa1 as a representative member of the Tpa1 family. Structures have been determined as a binary complex with Fe(III) and as a ternary complex with Fe(III) and 2OG. The structures reveal that both domains of Tpa1 have the double-stranded β-helix fold and are similar to prolyl 4-hydroxylases. However, the binding of Fe(III) and 2OG is observed in the N-terminal domain only. We also show that Tpa1 binds to poly(rA), suggesting its direct interaction with mRNA in the mRNP complex. The structural and functional data reported in this study support a role of the Tpa1 family as a hydroxylase in the mRNP complex and as an oxygen sensor

Structural Basis of Inhibition of DCLK1 by Ruxolitinib

Given the functional attributes of Doublecortin-like kinase 1 (DCLK1) in tumor growth, invasion, metastasis, cell motility, and tumor stemness, it is emerging as a therapeutic target in gastrointestinal cancers. Although a series of specific or nonspecific ATP-competitive inhibitors were identified against DCLK1, different types of scaffolds that can be utilized for the development of highly selective inhibitors or structural understanding of binding specificities of the compounds remain limited. Here, we present our work to repurpose a Janus kinase 1 inhibitor, ruxolitinib as a DCLK1 inhibitor, showing micromolar binding affinity and inhibitory activity. Furthermore, to gain an insight into its interaction mode with DCLK1, a crystal structure of the ruxolitinib-complexed DCLK1 has been determined and analyzed. Ruxolitinib as a nonspecific DCLK1 inhibitor characterized in this work is anticipated to provide a starting point for the structure-guided discovery of selective DCLK1 inhibitors

Structural insights into apoptotic regulation of human Bfk as a novel Bcl-2 family member

Bcl-2 family kin (Bfk), also known as Bcl-2-like 15, plays an essential role in regulating apoptosis by eliciting weak pro-apoptotic responses in the gastrointestinal tract. Human Bfk is a novel Bcl-2 family protein owing to its unique domain composition involving BH2 and BH3. However, the molecular mechanism underlying the regulation of apoptosis by Bfk remains unclear. Here, we first report the crystal structure of human full-length Bfk. Surprisingly, the structure of Bfk adopts a canonical Bcl-2 fold but lacks the hydrophobic cleft, which could accommodate a BH3 domain from other Bcl-2 family proteins. Our biophysical interaction analysis proved that the full-length Bfk itself does not interact with multi domain Bcl-2 family proteins or a BH3-containing peptide. Instead, Bfk is structurally and functionally reminiscent of Bid, a BH3-only protein in the Bcl-2 family, with similar conformations of helices alpha 3 -alpha 5 and the specific motif in helix alpha 5. Not only structural analyses of the full-length Bfk but also molecular dynamics simulation suggested that Bfk elicits its pro-apoptotic activity through a Bid-like apoptotic mechanism in which the BH3 domain is released upon caspase-mediated cleavage and a conformational change of the truncated form. Indeed, the BH3 peptide derived from Bfk exhibited in vitro interactions with Bcl-2, Bcl-X-L, and Bak. These findings provide new insights into the molecular characteristics of Bfk and a valuable foundation for development of a new therapeutic target to control apoptosis. (c) 2022 The Author(s). Published by Elsevier B.V. on behalf of Research Network of Computational and Structural Biotechnology. This is an open access article under the CC BY license (http://creativecommons. org/licenses/by/4.0/).N

ATP-dependent DNA ligase from Archaeoglobus fulgidus displays a tightly closed conformation

The crystal structure of an ATP-dependent DNA ligase from A. fulgidus has been determined. It resembles, but shows some variations from, the closed conformation of DNA ligase from P. furiosus

High expression of the phosphoinositide 3-kinase p110γ isoform can predict poor prognosis of non-small cell lung cancer

The protein p110γ is an isoform of the catalytic subunit of class I phosphoinositide 3-kinases (PI3Ks). PI3Ks are involved in the regulation of cell survival, growth, proliferation, and migration and have been implicated in the oncogenesis of various cancers. In this study, p110γ expression in non-small cell lung cancer (NSCLC) and its association with clinicopathological factors and patient survival were evaluated. A total of 230 NSCLC tumors were immunohistochemically stained for p110γ. Of these, 174 (75.7%) and 56 (24.3%) were placed in the low and high expression groups, respectively. The positive rate of p110γ was significantly higher in adenocarcinoma than in squamous cell carcinoma (p<0.001). Advanced stage NSCLCs showed higher p110γ expression than those at an early stage (p=0.002). Irrespective of the histological tumor type, the patients with high p110γ expression had significantly worse overall survival than those with low p110γ expression (p=0.004). p110γ expression was an independent poor prognostic factor in the multivariate analysis. Our results suggest that p110γ may be involved in the development and progression of NSCLC, and that p110γ has promising potential as a prognostic factor or novel therapeutic target for NSCLC

Overexpression, crystallization and preliminary X-­ray crystallographic analysis of phosphopantetheine adenylyltransferase from Enterococcus faecalis

Phosphopantetheine adenylyltransferase from En. faecalis was crystallized and X-ray diffraction data were collected to 2.70 Å resolution

Overexpression, crystallization and preliminary X-­ray crystallographic analysis of a putative transposase from Thermoplasma acidophilum encoded by the Ta0474 gene

A putative transposase from T. acidophilum encoded by the Ta0474 gene was crystallized and X-ray diffraction data were collected to 1.78 Å