Characterization of a SARS-CoV-2 spike protein reference material

Area of Science:

• Biochemistry
• Analytical Chemistry
• Biotechnology

Background:

• The COVID-19 pandemic highlighted the urgent need for standardized diagnostic tests.
• Rapid development of diagnostic assays led to variability and reliability issues.
• A standardized reference material for SARS-CoV-2 spike protein is crucial for assay validation.

Purpose of the Study:

• To develop and characterize a SARS-CoV-2 spike protein reference material (SMT1-1).
• To establish accurate molar and mass concentration values for SMT1-1.
• To ensure the homogeneity, stability, and reliability of the reference material.

Main Methods:

• Amino acid analysis (AAA) via liquid chromatography-tandem mass spectrometry (LC-ID-MS/MS).
• Ultraviolet-visible spectrophotometry (UV-Vis) for protein quantification.
• Size-exclusion liquid chromatography (LC-SEC) for oligomeric state and glycoprotein molar mass determination.

Main Results:

• The molar concentration of SMT1-1 was determined as 5.68 ± 0.22 µmol L⁻¹.
• The native trimeric spike protein constituted approximately 94% of the relative abundance.
• Mass concentration values for protein-only and intact glycoprotein were reported as 0.813 ± 0.030 mg mL⁻¹ and 1.050 ± 0.068 mg mL⁻¹, respectively.

Conclusions:

• SMT1-1 serves as a reliable reference material for SARS-CoV-2 spike protein.
• The established values support standardization and improve accuracy in COVID-19 diagnostic testing.
• This material aids the research community in overcoming challenges associated with assay variability.