Comparative Migration Studies最新文献

Enzymes are conformationally dynamic, and their dynamical properties play an important role in regulating their specificity and evolvability. In this context, substantial attention has been paid to the role of ligand-gated conformational changes in enzyme catalysis; however, such studies have focused on tremendously proficient enzymes such as triosephosphate isomerase and orotidine 5'-monophosphate decarboxylase, where the rapid (μs timescale) motion of a single loop dominates the transition between catalytically inactive and active conformations. In contrast, the (βα)₈-barrels of tryptophan and histidine biosynthesis, such as the specialist isomerase enzymes HisA and TrpF, and the bifunctional isomerase PriA, are decorated by multiple long loops that undergo conformational transitions on the ms (or slower) timescale. Studying the interdependent motions of multiple slow loops, and their role in catalysis, poses a significant computational challenge. This work combines conventional and enhanced molecular dynamics simulations with empirical valence bond simulations to provide rich details of the conformational behavior of the catalytic loops in HisA, PriA, and TrpF, and the role of their plasticity in facilitating bifunctionality in PriA and evolved HisA variants. In addition, we demonstrate that, similar to other enzymes activated by ligand-gated conformational changes, loops 3 and 4 of HisA and PriA act as gripper loops, facilitating the isomerization of the large bulky substrate ProFAR, albeit now on much slower timescales. This hints at convergent evolution on these different (βα)₈-barrel scaffolds. Finally, our work reemphasizes the potential of engineering loop dynamics as a tool to artificially manipulate the catalytic repertoire of TIM-barrel proteins.

For decades, Malaysia has been heavily dependent on unskilled and temporarily contracted migrant workers to fulfil labour gaps in the country. While Malaysia's economy continues to rely on migrant workers, the COVID-19 pandemic has further aggravated their precarious working and living conditions. In-depth interviews with Nepali migrant workers and community leaders in Malaysia and Nepal in 2021 revealed the incidence of labour rights violations, compounded by the lack of access to justice and effective remedies. Besides, workers are allegedly no longer benefiting from the competitive wages, subsequently limiting the value of their remittance to Nepal. We argue that these incidents serve as the drivers of the changing views of mobility, eventually influencing the emigration environment in which the social construction of migration exists in Nepal. This study examines the migratory realities in the Nepal-Malaysia migration corridor during the pandemic, subsequently contributing to current debate on the aspiration-ability model as a class of research.

This article explores how multiple, interrelated violence(s) shape the ways in which migrants relate to democratic politics transnationally. It takes as a departing point the literature on violent democracies and violent pluralism in the Latin American context, and more specifically the situation in Colombia, where democratic institutions coexist with plural violence(s). Following on from studies of migrant transnational politics, the analysis focuses on the Colombian diaspora and how migrants coming from violent democracies engage politically with the home country. Based on extensive research with Colombian migrants in Europe since the mid-90s, the article shows how despite different motivations for migrating, origin-country violence plays a significant role in the lives of many Colombians abroad. It then explores how violence influences migrants' transnational politics. Migrating from a context of pervasive violence(s) can affect migrants' sense of transnational belonging as well as increase mistrust and indifference towards formal democratic processes. However, the situation in the home country, together with being exposed to different conditions in the host society, can also motivate migrants to participate transnationally in initiatives to end the violence, thus increasing cooperation and trust.

To what extent has Covid-19 policy responses exacerbated the already existing multiple vulnerabilities of female migrants in Southern Africa? Using strategic conversations, the paper explores personal experiences of key conversants, to explore how gender blind policy responses to the pandemic have heightened female migrants' socio-economic challenges. The paper recommends gender sensitive and context specific policy responses to mitigate the existing socio-economic challenges.

[This corrects the article DOI: 10.1186/s40878-021-00275-9.].