tetano
Editor, Senior Moderator
Biophys J
. 2023 Jan 16;S0006-3495(23)00032-2.
doi: 10.1016/j.bpj.2023.01.016. Online ahead of print.
Interactions of SARS-CoV-2 and MERS-CoV Fusion Peptides Measured Using Single Molecule Force Methods
Cindy Qiu[SUP] 1 [/SUP], Gary R Whittaker[SUP] 2 [/SUP], Samuel H Gellman[SUP] 3 [/SUP], Susan Daniel[SUP] 1 [/SUP], Nicholas L Abbott[SUP] 1 [/SUP]
Affiliations
Abstract
We address the challenge of understanding how hydrophobic interactions are encoded by fusion peptide sequences within coronavirus (CoV) spike proteins. Within the fusion peptides of SARS-CoV-2 and MERS-CoV, a largely conserved peptide sequence called FP1 (SFIEDLLFNK and SAIEDLLFDK in SARS-2 and MERS, respectively) has been proposed to play a key role in encoding hydrophobic interactions that drive viral-host cell membrane fusion. While a non-polar triad (LLF) is common to both FP1 sequences, and thought to dominate the encoding of hydrophobic interactions, FP1 from SARS and MERS differ in two residues (Phe 2 versus Ala 2 and Asn 9 versus Asp 9s, respectively). Here we explore if single molecule force measurements can quantify hydrophobic interactions encoded by FP1 sequences, and then ask if sequence variations between FP1 from SARS-2 and MERS lead to significant differences in hydrophobic interactions. We find that both SARS-2 and MERS wild-type FP1 generate measurable hydrophobic interactions at the single molecule level, but that SARS-2 FP1 encodes a substantially stronger hydrophobic interaction than its MERS counterpart (1.91 ± 0.03 nN versus 0.68 ± 0.03 nN, respectively). By performing force measurements with FP1 sequences with single amino acid substitutions, we determine that a single residue mutation (Phe 2 versus Ala 2) causes the almost threefold difference in the hydrophobic interaction strength generated by the FP1 of SARS-2 versus MERS, despite the presence of LLF in both sequences. Infrared spectroscopy and circular dichroism measurements support the proposal that the outsized influence of Phe 2 versus Ala 2 on the hydrophobic interaction arises from variation in the secondary structure adopted by FP1. Overall, these insights reveal how single residue diversity in viral fusion peptides, including FP1 of SARS-CoV-2 and MERS-CoV, can lead to substantial changes in intermolecular interactions proposed to play a key role in viral fusion, and hint at strategies for regulating hydrophobic interactions of peptides in a range of contexts.
. 2023 Jan 16;S0006-3495(23)00032-2.
doi: 10.1016/j.bpj.2023.01.016. Online ahead of print.
Interactions of SARS-CoV-2 and MERS-CoV Fusion Peptides Measured Using Single Molecule Force Methods
Cindy Qiu[SUP] 1 [/SUP], Gary R Whittaker[SUP] 2 [/SUP], Samuel H Gellman[SUP] 3 [/SUP], Susan Daniel[SUP] 1 [/SUP], Nicholas L Abbott[SUP] 1 [/SUP]
Affiliations
- PMID: 36650897
- DOI: 10.1016/j.bpj.2023.01.016
Abstract
We address the challenge of understanding how hydrophobic interactions are encoded by fusion peptide sequences within coronavirus (CoV) spike proteins. Within the fusion peptides of SARS-CoV-2 and MERS-CoV, a largely conserved peptide sequence called FP1 (SFIEDLLFNK and SAIEDLLFDK in SARS-2 and MERS, respectively) has been proposed to play a key role in encoding hydrophobic interactions that drive viral-host cell membrane fusion. While a non-polar triad (LLF) is common to both FP1 sequences, and thought to dominate the encoding of hydrophobic interactions, FP1 from SARS and MERS differ in two residues (Phe 2 versus Ala 2 and Asn 9 versus Asp 9s, respectively). Here we explore if single molecule force measurements can quantify hydrophobic interactions encoded by FP1 sequences, and then ask if sequence variations between FP1 from SARS-2 and MERS lead to significant differences in hydrophobic interactions. We find that both SARS-2 and MERS wild-type FP1 generate measurable hydrophobic interactions at the single molecule level, but that SARS-2 FP1 encodes a substantially stronger hydrophobic interaction than its MERS counterpart (1.91 ± 0.03 nN versus 0.68 ± 0.03 nN, respectively). By performing force measurements with FP1 sequences with single amino acid substitutions, we determine that a single residue mutation (Phe 2 versus Ala 2) causes the almost threefold difference in the hydrophobic interaction strength generated by the FP1 of SARS-2 versus MERS, despite the presence of LLF in both sequences. Infrared spectroscopy and circular dichroism measurements support the proposal that the outsized influence of Phe 2 versus Ala 2 on the hydrophobic interaction arises from variation in the secondary structure adopted by FP1. Overall, these insights reveal how single residue diversity in viral fusion peptides, including FP1 of SARS-CoV-2 and MERS-CoV, can lead to substantial changes in intermolecular interactions proposed to play a key role in viral fusion, and hint at strategies for regulating hydrophobic interactions of peptides in a range of contexts.