Resonance assignment and secondary structure of the middle MA-3 domain and complete tandem MA-3 region of the tumour suppressor protein Pdcd4

Pdcd4 (Programmed Cell Death Protein 4) is a novel eukaryotic tumour suppressor protein, which is involved in the regulation of both transcription and translation (reviewed in Lankat-Buttgereit and Göke 2009). The protein contains two interacting MA-3 domains (MA-3M and MA-3C), which are linked by a short semi-flexible linker region (Waters et al. 2007; Suzuki et al. 2008). The MA-3 domains are involved in mediating specific protein–protein interactions with functional partners such as eIF4A (Yang et al. 2003). Here we report essentially complete backbone and side chain 15N, 13C and 1H assignments for a construct composed of the middle MA-3 domain and subsequent linker region (MA-3M) and backbone assignments for the entire tandem MA-3 region of Pdcd4 (Pdcd4 MA-3M-C). Analysis of the backbone chemical shift data obtained indicates that Pdcd4 MA-3M contains eight helical regions corresponding to over 74% of the protein backbone and that Pdcd4 MA-3M-C contains fifteen helical regions (72%). Comparison of the position of these helical regions with those observed in the crystal structures suggests that the solution and crystal structures of both proteins are very similar

Assessing the potential of acoustic telemetry to underpin the regional management of basking sharks (Cetorhinus maximus)

Acoustic telemetry can provide valuable space-use data for a range of marine species. Yet the deployment of species-specific arrays over vast areas to gather data on highly migratory vertebrates poses formidable challenges, often rendering it impractical. To address this issue, we pioneered the use of acoustic telemetry on basking sharks (Cetorhinus maximus) to test the feasibility of using broadscale, multi-project acoustic receiver arrays to track the movements of this species of high conservation concern through the coastal waters of Ireland, Northern Ireland, and Scotland. Throughout 2021 and 2022, we tagged 35 basking sharks with acoustic transmitters off the west coast of Ireland; 27 of these were detected by 96 receiver stations throughout the study area (n = 9 arrays) with up to 216 detections of an individual shark (mean = 84, s.d. 65). On average, sharks spent ~ 1 day at each acoustic array, with discrete residency periods of up to nine days. Twenty-one sharks were detected at multiple arrays with evidence of inter-annual site fidelity, with the same individuals returning to the same locations in Ireland and Scotland over 2 years. Eight pairs of sharks were detected within 24 h of each other at consecutive arrays, suggesting some level of social coordination and synchronised movement. These findings demonstrate how multi-project acoustic telemetry can support international, cost-effective monitoring of basking sharks and other highly mobile species. Decision support tools such as these can consolidate cross-border management strategies, but to achieve this goal, collaborative efforts across jurisdictions are necessary to establish the required infrastructure and secure ongoing support

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Molecular features governing the stability and specificity of functional complex formation by Mycobacterium tuberculosis CFP-10/ESAT-6 family proteins

The Mycobacterium tuberculosis complex CFP-10/ESAT-6 family proteins play essential but poorly defined roles in tuberculosis pathogenesis. In this article we report the results of detailed spectroscopic studies of several members of the CFP10/ESAT-6 family. This work shows that the CFP-10/ESAT-6 related proteins, Rv0287 and Rv0288, form a tight 1:1 complex, which is predominantly helical in structure and is predicted to closely resemble the complex formed by CFP-10 and ESAT-6. In addition, the Rv0287.Rv0288 complex was found to be significantly more stable to both chemical and temperature induced denaturation than CFP-10.ESAT-6. This approach demonstrated that neither Rv0287.Rv0288 nor the CFP-10.ESAT-6 complexes are destabilized at low pH (4.5), indicating that even in low pH environments, such as the mature phagosome, both Rv0287.Rv0288 and CFP-10.ESAT-6 undoubtedly function as complexes rather than individual proteins. Analysis of the structure of the CFP-10.ESAT-6 complex and optimized amino acid sequence alignments of M. tuberculosis CFP-10/ESAT-6 family proteins revealed that residues involved in the intramolecular contacts between helices are conserved across the CFP-10/ ESAT-6 family, but not those involved in primarily intermolecular contacts. This analysis identified the molecular basis for the specificity and stability of complex formation between CFP-10/ ESAT-6 family proteins, and indicates that the formation of functional complexes with key roles in pathogenesis will be limited to genome partners, or very closely related family members, such as Rv0287/Rv0288 and Rv3019c/Rv3020c

Interaction of the Transactivation Domain of B-Myb with the TAZ2 Domain of the Coactivator p300: Molecular Features and Properties of the Complex

<div><p>The transcription factor B-Myb is a key regulator of the cell cycle in vertebrates, with activation of transcription involving the recognition of specific DNA target sites and the recruitment of functional partner proteins, including the coactivators p300 and CBP. Here we report the results of detailed studies of the interaction between the transactivation domain of B-Myb (B-Myb TAD) and the TAZ2 domain of p300. The B-Myb TAD was characterized using circular dichroism, fluorescence and NMR spectroscopy, which revealed that the isolated domain exists as a random coil polypeptide. Pull-down and spectroscopic experiments clearly showed that the B-Myb TAD binds to p300 TAZ2 to form a moderately tight (K_d ∼1.0–10 µM) complex, which results in at least partial folding of the B-Myb TAD. Significant changes in NMR spectra of p300 TAZ2 suggest that the B-Myb TAD binds to a relatively large patch on the surface of the domain (∼1200 Ų). The apparent B-Myb TAD binding site on p300 TAZ2 shows striking similarity to the surface of CBP TAZ2 involved in binding to the transactivation domain of the transcription factor signal transducer and activator of transcription 1 (STAT1), which suggests that the structure of the B-Myb TAD-p300 TAZ2 complex may share many features with that reported for STAT1 TAD-p300 TAZ2.</p> </div

Interaction of the transactivation domain of B-Myb with the TAZ2 domain of the coactivator p300: molecular features and properties of the complex.

The transcription factor B-Myb is a key regulator of the cell cycle in vertebrates, with activation of transcription involving the recognition of specific DNA target sites and the recruitment of functional partner proteins, including the coactivators p300 and CBP. Here we report the results of detailed studies of the interaction between the transactivation domain of B-Myb (B-Myb TAD) and the TAZ2 domain of p300. The B-Myb TAD was characterized using circular dichroism, fluorescence and NMR spectroscopy, which revealed that the isolated domain exists as a random coil polypeptide. Pull-down and spectroscopic experiments clearly showed that the B-Myb TAD binds to p300 TAZ2 to form a moderately tight (K(d) ~1.0-10 µM) complex, which results in at least partial folding of the B-Myb TAD. Significant changes in NMR spectra of p300 TAZ2 suggest that the B-Myb TAD binds to a relatively large patch on the surface of the domain (~1200 Å(2)). The apparent B-Myb TAD binding site on p300 TAZ2 shows striking similarity to the surface of CBP TAZ2 involved in binding to the transactivation domain of the transcription factor signal transducer and activator of transcription 1 (STAT1), which suggests that the structure of the B-Myb TAD-p300 TAZ2 complex may share many features with that reported for STAT1 TAD-p300 TAZ2