2028
Cotranslational folding of alkaline phosphatase in the periplasm of Escherichia coli
Rageia Elfageih, Alexandros Karyolaimos, Grant Kemp, Jan‐Willem de Gier, Gunnar von Heijne, and Renuka Kudva
Proteins are made by ribosomes and often start to fold cotranslationally, even before the whole protein has been synthesized. In recent years, new methods that make it possible to follow the cotranslational folding of cytoplasmic proteins inside or just outside the ribosome have been developed. Kudva et al. now present a variation on the so‐called Force Profile Analysis method that allows them to follow the folding of proteins that are cotranslationally transported into the periplasm and hence fold only at large distances from the ribosome, and detect disulfid‐estabilized periplasmic folding intermediates formed during translation of E. coli alkaline phosphatase. https://onlinelibrary.wiley.com/doi/10.1002/pro.3927
2038
Comparing the binding properties of peptides mimicking the Envelope protein of SARS‐CoV and SARS‐CoV‐2 to the PDZ domain of the tight junction‐associated PALS1 protein
Angelo Toto, Sana Ma, Francesca Malagrinò, Lorenzo Visconti, Livia Pagano, Kristian Stromgaard, and Stefano Gianni
The Envelope protein is one of the four major structural proteins expressed by the viral genome of Coronaviruses. It is largely expressed in the host intracellular environment and has a key role in the virulence processes, yet being poorly present in the mature virus. We investigated the binding reaction between the C‐terminal portion of the Envelope proteins from SARS‐CoV and SARS‐CoV‐2 and the PDZ domain of PALS1, an interaction suggested to have a primary role in lung epithelia disruption upon SARS‐CoV and SARS‐CoV‐2 infection. Our results support the hypothesis that an increased binding affinity of the Envelope protein of SARS‐CoV‐2 to the PDZ domain of PALS1 may be at the basis of the characteristic virulence of this virus. https://onlinelibrary.wiley.com/doi/10.1002/pro.3936
2054
Crystal structure of the nucleotide‐metabolizing enzyme NTPDase4
Alexei Gorelik, Jonathan M. Labriola, Katalin Illes, and Bhushan Nagar
The ecto‐nucleoside triphosphate diphosphohydrolases (NTPDases) are enzymes that participate in intercellular signaling processes, and also serve recycling roles in intracellular nucleotide metabolism. The 3D structures of signaling NTPDases are known, however the structures of the recycling family members have not been determined. Here, the crystal structure of NTPDase4 is reported. The enzyme adopts an open, inactive conformation, with its active site residues far apart. Features that grant its substrate selectivity are described, and its potential interaction with membranes is discussed. https://onlinelibrary.wiley.com/doi/10.1002/pro.3926
2075
A phage‐displayed single‐chain Fab library optimized for rapid production of single‐chain IgGs
Rachel Hanna, Lia Cardarelli, Nish Patel, Levi L. Blazer, and Jarrett J. Adams, Sachdev S. Sidhu
The conversion of phage‐displayed antibody fragments (Fabs) to full‐length IgGs is costly and time‐consuming. Since IgGs represent the modality of choice for most therapeutic applications, we sought to improve this workflow by designing a new library more amenable to Fab‐to‐IgG cloning. We developed a highly diverse single‐chain Fab (scFab) library from which pools of selected scFabs can be rapidly converted to scIgGs for biochemical characterization. We show that scIgGs recapitulate the affinities and specificities of conventional IgGs, and thus, the scFab library provides a facile means to more directly screen for IgGs with desired characteristics. https://onlinelibrary.wiley.com/doi/10.1002/pro.3931
