title: The SARS-CoV heptad repeat 2 exhibits pH-induced helix formation.
abstract: The heptad repeats 1 and 2 of SARS-CoV spike, termed HR1 and HR2, play critical roles in viral entry. Moreover, HR1 and HR2 derived free peptides are inhibitors of SARS-CoV entry. In this work we used circular dichroism to show that HR2 helix formation is induced at pH 5, the pH of the endosome. In addition, we demonstrate that the HR2 helix is further stabilized at physiological ionic strengths. Together, these observations provide new insight into the mechanism of SARS-CoV entry and suggest that HR2 may be an attractive target for therapeutic intervention.
authors.affiliation: Department of Biochemistry & Molecular Genetics University of Illinois at Chicago, Chicago, IL 60607, USA.
authors.forename: Jessica
authors.initials: J
authors.lastname: Celigoy
authors.forename: Susanna
authors.initials: S
authors.lastname: McReynolds
authors.forename: Michael
authors.initials: M
authors.lastname: Caffrey
mesh_terms: D002942:Circular Dichroism; D006863:Hydrogen-Ion Concentration; D017433:Protein Structure, Secondary; D020449:Repetitive Sequences, Amino Acid; D045473:Severe acute respiratory syndrome-related coronavirus / Q000737:chemistry*; D055672:Static Electricity; D053586:Virus Internalization