Structural basis for different substrate profiles of two closely related class D β-lactamases and their inhibition by halogens

OXA-163 and OXA-48 are closely related class D β-lactamases that exhibit different substrate profiles. OXA-163 hydrolyzes oxyimino-cephalosporins, particularly ceftazidime, while OXA-48 prefers carbapenem substrates. OXA-163 differs from OXA-48 by one substitution (S212D) in the active-site β5 strand and a four-amino acid deletion (214-RIEP-217) in the loop connecting the β5 and β6 strands. Although the structure of OXA-48 has been determined, the structure of OXA-163 is unknown. To further understand the basis for their different substrate specificities, we performed enzyme kinetic analysis, inhibition assays, X-ray crystallography, and molecular modeling. The results confirm the carbapenemase nature of OXA-48 and the ability of OXA-163 to hydrolyze the oxyimino-cephalosporin ceftazidime. The crystal structure of OXA-163 determined at 1.72 Å resolution reveals an expanded active site compared to that of OXA-48, which allows the bulky substrate ceftazidime to be accommodated. The structural differences with OXA-48, which cannot hydrolyze ceftazidime, provide a rationale for the change in substrate specificity between the enzymes. OXA-163 also crystallized under another condition that included iodide. The crystal structure determined at 2.87 Å resolution revealed iodide in the active site accompanied by several significant conformational changes, including a distortion of the β5 strand, decarboxylation of Lys73, and distortion of the substrate-binding site. Further studies showed that both OXA-163 and OXA-48 are inhibited in the presence of iodide. In addition, OXA-10, which is not a member of the OXA-48-like family, is also inhibited by iodide. These findings provide a molecular basis for the hydrolysis of ceftazidime by OXA-163 and, more broadly, show how minor sequence changes can profoundly alter the active-site configuration and thereby affect the substrate profile of an enzyme

The dynamics of genome replication using deep sequencing

Peer reviewedPublisher PD

PROJECT MANAGER COMPETENCIES AND PERFORMANCE OUTCOMES IN IT PROJECTS

Meeting performance targets for IT projects is difficult, and skilled project managers have been identified as a key factor in maximizing the possibilities of success. Our goal in this study was to identify critical behavioural competencies for IT project managers, including competencies necessary for entry-level positions and competencies that distinguish superior performance in IT project management. Two categories of competence, team leadership and concern for order, were associated with higher levels of IT project performance outcomes. The behaviours within these two categories provide a useful focus for organizations seeking to improve their project management performance. Some of these behaviours - for example, detailed planning and managing meetings - are entry-level behaviours that should be the target of basic training for novice project managers. Other behaviours - for example, accurate estimation and problem solving strategies - were observed in fewer respondents and could be the focus of more advanced training for incumbent project managers. Additionally, two valuable but infrequently observed behaviours ? creating a compelling vision and ensuring alignment with business strategic goals ? were correlated with performance related to supporting longer term business benefits from IT projects, suggesting that developing project manager competence in these behaviours would be particularly beneficial for achieving long-term success from IT projects

Calling for a Revolution:An Analysis of IoT Manifestos

Designers and developers are increasingly writing manifestos to express frustration and uncertainty as they struggle to negotiate between the possibilities that IoT technologies offer and the ethical concerns they engender. Manifestos are defining of a “moment of crisis” and their recent proliferation indicates a desire for change. We analyze the messages manifesto authors have for their readers. Emerging from a sense of uncertainty, these manifestos create publics for debate, demand attention and call for change. While manifestos provide potential roadmaps for a better future, they also express a deep concern and even fear of the state of the world and the role of technology in it. We highlight how practitioners are responding to unstable and rapidly changing times and detail what solutions they envision, and what conflicts these might bring about. Our analysis suggests new ways HCI might theorize and design for responsibility while attending to the perils of responsibilisation

Behavioral Competencies and Learning Methods for IT Project Management: An Exploratory Study

What do IT project managers consider to be the critical skills necessary for project success, and how have they developed those skills? The aim of this research has been to answer these questions. We interviewed 23 experienced IT project managers from 11 organizations, focusing first on what the managers perceived as their most critical project management skills, and then on how they had developed those skills. We also discussed their exposure to a wide variety of organizational development interventions. By focusing on how project managers actually learned critical skills, we have been able to uncover the importance of informal learning channels, often involving project experiences, for the development of IT project management skills

Information Technology Project Risk Management: Bridging the Gap between Research and Practice

The gap between research and practice is strikingly evident in the area of information technology (IT) project risk management. In spite of extensive research for over 30 years into IT project risk factors resulting in normative guidance on IT project risk management, adoption of these risk management methods in practice is inconsistent. Managing risk in IT projects remains a key challenge for many organizations. We discuss barriers to the application of normative prescriptions, such as assessments of probability and impact of risk, and suggest a contingency approach, which addresses the uncertainties, complexities, and ambiguities of IT projects and enables early identification of high-risk projects. Specifically, in a case study, we examine how the project management office (PMO) at one organization has bridged the gap between research and practice, developing a contingency-based risk assessment process well founded on research knowledge of project dimensions related to project performance, while also being practical in its implementation. The PMO\u27s risk assessment process, and the risk spider chart that is the primary tool in this assessment, has proven to be effective for surfacing inherent risk at the early stages of IT projects, thereby enabling the recommendation of appropriate management strategies. The PMO\u27s project risk assessment process is a model for other organizations striving to engage in effective and collaborative practices in order to improve project outcomes. The case illustrates the importance of considering the practical constraints of the context of application in order to transform research findings into practices that promote attainment of desired outcomes