title: Understanding allosteric enzyme regulation using macromolecular rate theory

authors: Hamill, Carlin James

subjects: Enzyme

abstract: Enzyme catalysed reaction rates produce a curved temperature dependence with a temperature optimum, Topt. Traditionally enzyme temperature dependence has been modelled by the Arrhenius and Eyring-Polanyi equations. Deviations from
these models at elevated temperatures have traditionally been attributed to enzyme denaturation. Increasing evidence shows that enzyme denaturation is insufficient to fully explain the curvature for enzyme catalysed rates with temperature.

Macromolecular rate theory (MMRT) accounts for these deviations from early models by introducing the concept of heat capacity (Cp). During an enzymatic reaction, the heat capacity is reduced as the transition state complex forms (due to enzyme rigidification), resulting in an overall negative change in heat capacity (ΔCp^‡) for the reaction. Heat capacity is a function of the number and energies of the vibrational modes for the individual molecules. Enzyme-ligand binding will influence the energies of the vibrational modes of the molecular complex
therefore affecting an enzymes’ heat capacity and its catalytic rate via ΔCp^‡. Notably, a form of enzyme regulation (called allostery) utilises ligand binding at a site other than the active site to effect changes in catalytic rate.

The underlying mechanisms of allostery are poorly understood. Here, the mechanisms of allostery are explored using a model isomaltase enzyme and MMRT to investigate changes in heat capacity. Several mutants of the model MalL enzyme were designed, produced and purified. These mutations aimed to either
alter the structural integrity or mimic ligand binding in the C-terminal domain. Using a Stopped-Flow apparatus, these mutants were characterised kinetically and using crystallographic techniques, two structures were solved at high resolution.

Targeted mutations approximately 30 Å from the active site showed significant changes in enzyme rate. Overall, the two new structures of MalL were very similar to the apo-enzyme showing only very minor structural deviations. Changes to the rate can thus be attributed to changes in enzyme dynamics and heat capacity.
These results are a promising first step in linking changes in enzymatic activity with changes to enzyme dynamics and heat capacity, using MMRT as a model.

text: Understanding allosteric enzyme regulation using macromolecular rate theory Enzyme catalysed reaction rates produce a curved temperature dependence with a temperature optimum, Topt. Traditionally enzyme temperature dependence has been modelled by the Arrhenius and Eyring-Polanyi equations. Deviations from
these models at elevated temperatures have traditionally been attributed to enzyme denaturation. Increasing evidence shows that enzyme denaturation is insufficient to fully explain the curvature for enzyme catalysed rates with temperature.

Macromolecular rate theory (MMRT) accounts for these deviations from early models by introducing the concept of heat capacity (Cp). During an enzymatic reaction, the heat capacity is reduced as the transition state complex forms (due to enzyme rigidification), resulting in an overall negative change in heat capacity (ΔCp^‡) for the reaction. Heat capacity is a function of the number and energies of the vibrational modes for the individual molecules. Enzyme-ligand binding will influence the energies of the vibrational modes of the molecular complex
therefore affecting an enzymes’ heat capacity and its catalytic rate via ΔCp^‡. Notably, a form of enzyme regulation (called allostery) utilises ligand binding at a site other than the active site to effect changes in catalytic rate.

The underlying mechanisms of allostery are poorly understood. Here, the mechanisms of allostery are explored using a model isomaltase enzyme and MMRT to investigate changes in heat capacity. Several mutants of the model MalL enzyme were designed, produced and purified. These mutations aimed to either
alter the structural integrity or mimic ligand binding in the C-terminal domain. Using a Stopped-Flow apparatus, these mutants were characterised kinetically and using crystallographic techniques, two structures were solved at high resolution.

Targeted mutations approximately 30 Å from the active site showed significant changes in enzyme rate. Overall, the two new structures of MalL were very similar to the apo-enzyme showing only very minor structural deviations. Changes to the rate can thus be attributed to changes in enzyme dynamics and heat capacity.
These results are a promising first step in linking changes in enzymatic activity with changes to enzyme dynamics and heat capacity, using MMRT as a model.

year: 2020

title: Responding to an international crisis: The adaptability of the practice of work-integrated learning

authors: Zegwaard, Karsten E.

subjects: COVID-19

abstract: The impact of the COVID-19 pandemic on the practice of work-integrated learning (WIL) has been significant, with many active WIL activities pivoting to remote offerings where students engage with the workplace through online platforms from their homes. The pandemic has also caused significant and ongoing disruption to the economy, likely causing less work placement opportunities for upcoming years within the context of limited institutional budgets and resourcing. It is, therefore, vitally important that institutions develop diverse practices of WIL and shift away from a heavy reliance on work placements. Developing diverse WIL practices across educational institutions is an important strategy to build 'institutional WIL resilience' during times of disrupted economies with limited WIL opportunities. During the pandemic, the use of simulations had increased, in particular, in relation to preparing students for WIL, however, caution is needed in considering simulations as a comparable alternative to WIL.

text: Responding to an international crisis: The adaptability of the practice of work-integrated learning The impact of the COVID-19 pandemic on the practice of work-integrated learning (WIL) has been significant, with many active WIL activities pivoting to remote offerings where students engage with the workplace through online platforms from their homes. The pandemic has also caused significant and ongoing disruption to the economy, likely causing less work placement opportunities for upcoming years within the context of limited institutional budgets and resourcing. It is, therefore, vitally important that institutions develop diverse practices of WIL and shift away from a heavy reliance on work placements. Developing diverse WIL practices across educational institutions is an important strategy to build 'institutional WIL resilience' during times of disrupted economies with limited WIL opportunities. During the pandemic, the use of simulations had increased, in particular, in relation to preparing students for WIL, however, caution is needed in considering simulations as a comparable alternative to WIL.

year: 2020

title: Understanding the Happiness of Māori and the Role of Consumption: Experiences of the Millennial Generation

authors: de Thierry, Ebony

subjects: Māori Well-Being

abstract: Happiness is commonly perceived as the ideal state of being for  all of human kind. Although a universal definition of the term remains elusive, happiness is a goal that everybody wants to achieve. In understanding the different aspects that shape happiness, the literature has shown that this can vary depending on the cultural context. As such, this study investigates the essence of happiness as it is experienced by Māori. In understanding the experiences of the Millennial generation, the role that consumption plays is also explored. This group of young adults have been raised in an era when consumerism and cultural revitalisation are the norm.  

This investigation was guided by hermeneutic phenomenology using a kaupapa Māori research perspective. Through this, thirteen young Māori individuals were interviewed to gain their experiences of happiness. Photo elicitation techniques were utilised as a means to facilitate these interviews. Stories of the participants’ experiences of happiness were crafted and then analysed to explore the role of consumption.

Findings show that the happiness of Māori is shaped by the five themes of; sense of belonging, whānau and relationships, spirituality, achievement and success, and sense of freedom. These themes interrelate as they are underpinned by the collective values of Māori. In particular, the aspects of spirituality and sense of belonging appear to be specific to the Māori realm. These are based on customs, values and beliefs that are inherited from our ancestors yet are still prevalent today. In terms of consumption, happiness can be positively linked to experiential consumption. In this case, it can play three different roles on the happiness of Māori through either; a direct connection, an indirect connection, or a negative connection. For Māori, consumption is more likely to have an indirect connection. This implies that it is able to facilitate, maintain and enhance happiness, but is not essential to creating these feelings. This investigation contributes to the literature in four ways. First, this study serves as a starting point to developing a comprehensive framework of happiness that is specific to the culture, views and values of Māori. This will assist Māori through ensuring that they are accurately represented in policies, frameworks and statistics. Second, it proposes five guidelines for Māori which suggest how they can maximise happiness through consumption. Third, this study provides a more up-to-date understanding of the happiness of Māori at the individual level whilst incorporating the impact of collective values. Marketers, researchers and practitioners can utilise this information in an attempt to aid in improving the happiness of Māori society. Finally, it shows that consumption can continue to be positively related to happiness once basic needs have been met. The positive role that consumption can play on happiness is identified, showing that marketers and consumers can work together to achieve happiness.

text: Understanding the Happiness of Māori and the Role of Consumption: Experiences of the Millennial Generation Happiness is commonly perceived as the ideal state of being for  all of human kind. Although a universal definition of the term remains elusive, happiness is a goal that everybody wants to achieve. In understanding the different aspects that shape happiness, the literature has shown that this can vary depending on the cultural context. As such, this study investigates the essence of happiness as it is experienced by Māori. In understanding the experiences of the Millennial generation, the role that consumption plays is also explored. This group of young adults have been raised in an era when consumerism and cultural revitalisation are the norm.  

This investigation was guided by hermeneutic phenomenology using a kaupapa Māori research perspective. Through this, thirteen young Māori individuals were interviewed to gain their experiences of happiness. Photo elicitation techniques were utilised as a means to facilitate these interviews. Stories of the participants’ experiences of happiness were crafted and then analysed to explore the role of consumption.

Findings show that the happiness of Māori is shaped by the five themes of; sense of belonging, whānau and relationships, spirituality, achievement and success, and sense of freedom. These themes interrelate as they are underpinned by the collective values of Māori. In particular, the aspects of spirituality and sense of belonging appear to be specific to the Māori realm. These are based on customs, values and beliefs that are inherited from our ancestors yet are still prevalent today. In terms of consumption, happiness can be positively linked to experiential consumption. In this case, it can play three different roles on the happiness of Māori through either; a direct connection, an indirect connection, or a negative connection. For Māori, consumption is more likely to have an indirect connection. This implies that it is able to facilitate, maintain and enhance happiness, but is not essential to creating these feelings. This investigation contributes to the literature in four ways. First, this study serves as a starting point to developing a comprehensive framework of happiness that is specific to the culture, views and values of Māori. This will assist Māori through ensuring that they are accurately represented in policies, frameworks and statistics. Second, it proposes five guidelines for Māori which suggest how they can maximise happiness through consumption. Third, this study provides a more up-to-date understanding of the happiness of Māori at the individual level whilst incorporating the impact of collective values. Marketers, researchers and practitioners can utilise this information in an attempt to aid in improving the happiness of Māori society. Finally, it shows that consumption can continue to be positively related to happiness once basic needs have been met. The positive role that consumption can play on happiness is identified, showing that marketers and consumers can work together to achieve happiness.

year: 2012