Most efforts to understand macromolecular crowding focus on global (i.e., complete) unfolding, but smaller excursions, often called breathing, promote aggregation, which is associated with several diseases and the bane of pharmaceutical and commercial protein production. We used NMR to assess the effects of ethylene glycol (EG) and polyethylene glycols (PEGs) on the structure and stability of the B1 domain of protein G (GB1). Our data show that EG and PEGs stabilize GB1 differently. EG interacts with GB1 more strongly than PEGs, but neither affects the structure of the folded state. EG and 12000 g/mol PEG stabilize GB1 more than PEGs of intermediate size, but EG and smaller PEGs stabilize GB1 enthalpically while the largest PEG acts entropically. Our key finding is that PEGs turn local unfolding into global unfolding, and meta-analysis of published data supports this conclusion. These efforts provide knowledge that can be applied to improve biological drugs and commercial enzymes.

To support efforts to stem the proliferation of chemical weapons (CWs), we have curated and structurally annotated CW-control lists from three key international nonproliferation frameworks: the Chemical Weapons Convention (CWC), the Australia Group (AG), and the Wassenaar Arrangement. The curated lists are available as web tables at the Costanzi Research website (). The annotations include manually curated 2D structural images, which provide a means to appreciate at a glance the similarities and differences between different entries, as well as downloadable 2D structures, in two different formats and three different structural identifiers, namely, simplified molecular-input line-entry system, standard InChI, and standard InChIKey, which are intended to provide a platform for cheminformatics analyses. The tables also include links to National Center for Biotechnology Information’s PubChem and National Institute of Standards and Technology’s Chemistry WebBook cards, hence providing prompt access to a wealth of physicochemical, analytical chemistry, and toxicological information. To showcase the importance of structural annotations, we discuss a discrepancy in a CW-control list covering the defoliant Agent Orange, which we identified through our curation process, and propose a solution to address it. Moreover, we present the results of chemical fingerprinting analyses, through which we clustered the entries of the three CW-control lists under study into structurally related groups and studied the overlaps between the three lists. As an application of this study, we examine the recent updates of CWC Schedule 1 and the AG precursors list, highlighting the relationships between the two amendments and proposing the possible addition of further chemicals. Our research is intended to facilitate the communication between scientific advisors and policymakers as well as the work of chemists and cheminformaticians involved in the CW nonproliferation field. Ultimately, we seek to provide tools to bolster the control of CWs and support the global efforts to rid the world of this category of weapons.

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