ORCID Profile
0000-0001-7648-2163
Current Organisation
University of California, Berkeley
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Publisher: Cold Spring Harbor Laboratory
Date: 31-08-2020
DOI: 10.1101/2020.08.30.274340
Abstract: In addition to encoding the final tertiary fold and stability, the primary sequence of a protein encodes the folding trajectory and kinetic barriers that determines the speed of folding. How these kinetic barriers are encoded by the sequence is not well understood. Here, we use evolutionary sequence variation in the alpha-lytic protease (αLP) protein family to probe the relationship between sequence and energy landscape. αLP has an unusual energy landscape: the native state of αLP is not the most thermodynamically favored conformation and, instead, it remains folded due to a large kinetic barrier preventing unfolding. In order to fold, αLP utilizes an N-terminal pro region of similar size to the protease itself that functions as a folding catalyst. Once folded, the pro region is removed, and the native state does not unfold on a biologically relevant timescale. Without the pro region, αLP folds on the order of millennia. A phylogenetic search uncovers αLP homologs with a wide range of pro-region sizes, including some with no pro region at all. In the resulting phylogenetic tree, these homologs cluster by pro-region size. Homologs naturally lacking pro regions are thermodynamically stable, fold much faster than αLP, yet retain the same fold as αLP. Key amino acids thought to contribute to αLP’s extreme kinetic stability are lost in these homologs, further supporting their role in kinetic stability. This study highlights how the entire energy landscape plays an important role in determining the evolutionary pressures on and changes to the protein sequence.
Publisher: Cold Spring Harbor Laboratory
Date: 20-07-2021
DOI: 10.1101/2021.07.20.453126
Abstract: The catalytic activity of Syk-family tyrosine kinases is regulated by a tandem-SH2 module (tSH2 module). In the autoinhibited state, this module adopts a conformation which stabilizes an inactive conformation of the kinase domain. The binding of the tSH2 module to doubly-phosphorylated tyrosine-containing motifs necessitates a conformational change, thereby relieving kinase inhibition and promoting activation. We determined the crystal structure of the isolated tSH2 module of Syk and find, in contrast to ZAP-70, that its conformation more closely resembles that of the peptide-bound state, rather than the autoinhibited state. Hydrogen-deuterium exchange by mass spectrometry, as well as molecular dynamics simulations, reveal that the dynamics of the tSH2 modules of Syk and ZAP-70 differ, with most of these differences occurring in the C-terminal SH2 domain. Our data suggest that the conformational landscapes of the tSH2 modules in Syk and ZAP-70 have been tuned differently, such that the auto-inhibited conformation of the Syk tSH2 module is less stable. This feature of Syk likely contributes to its ability to more readily escape autoinhibition when compared to ZAP-70, consistent with tighter control of downstream signaling pathways in T cells.
Publisher: eLife Sciences Publications, Ltd
Date: 21-02-2023
Publisher: eLife Sciences Publications, Ltd
Date: 21-03-2023
DOI: 10.7554/ELIFE.83710
Abstract: To address the ongoing SARS-CoV-2 pandemic and prepare for future coronavirus outbreaks, understanding the protective potential of epitopes conserved across SARS-CoV-2 variants and coronavirus lineages is essential. We describe a highly conserved, conformational S2 domain epitope present only in the prefusion core of β-coronaviruses: SARS-CoV-2 S2 apex residues 980–1006 in the flexible hinge. Antibody RAY53 binds the native hinge in MERS-CoV and SARS-CoV-2 spikes on the surface of mammalian cells and mediates antibody-dependent cellular phagocytosis and cytotoxicity against SARS-CoV-2 spike in vitro. Hinge epitope mutations that ablate antibody binding compromise pseudovirus infectivity, but changes elsewhere that affect spike opening dynamics, including those found in Omicron BA.1, occlude the epitope and may evade pre-existing serum antibodies targeting the S2 core. This work defines a third class of S2 antibody while providing insights into the potency and limitations of S2 core epitope targeting.
Publisher: Wiley
Date: 23-10-2021
DOI: 10.1002/PRO.4199
Abstract: The catalytic activity of Syk‐family tyrosine kinases is regulated by a tandem Src homology 2 module (tSH2 module). In the autoinhibited state, this module adopts a conformation that stabilizes an inactive conformation of the kinase domain. The binding of the tSH2 module to phosphorylated immunoreceptor tyrosine‐based activation motifs necessitates a conformational change, thereby relieving kinase inhibition and promoting activation. We determined the crystal structure of the isolated tSH2 module of Syk and find, in contrast to ZAP‐70, that its conformation more closely resembles that of the peptide‐bound state, rather than the autoinhibited state. Hydrogen–deuterium exchange by mass spectrometry, as well as molecular dynamics simulations, reveal that the dynamics of the tSH2 modules of Syk and ZAP‐70 differ, with most of these differences occurring in the C‐terminal SH2 domain. Our data suggest that the conformational landscapes of the tSH2 modules in Syk and ZAP‐70 have been tuned differently, such that the autoinhibited conformation of the Syk tSH2 module is less stable. This feature of Syk likely contributes to its ability to more readily escape autoinhibition when compared to ZAP‐70, consistent with tighter control of downstream signaling pathways in T cells.
Location: United States of America
Location: United States of America
No related grants have been discovered for Susan Marqusee.