Expression, purification and characterization of the small hydrophobic (SH) protein of human respiratory syncytial virus (hRSV) : the role of his 22 and his 51 on stabilization of hRSV SH proteins in detergents.

• Main Author: Zhou, Yichao.
• Other Authors: Jaume Torres
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Science::Biological sciences::Microbiology::Virology
• Online Access: http://hdl.handle.net/10356/39782
• Institution: Nanyang Technological University

SH protein of hRSV is a small hydrophobic membrane glycoprotein containing a single-transmembrane domain. Each SH protein contains two protonatable histidine residues: His22 near the N terminal in transmembrane domain and His51 in the C terminal outside transmembrane domain. Previous studies showed that SH proteins form pentamer with the His22 and His51 of each monomer facing the lumen, suggesting that these histidines might be involved in this pentamerization. To find out the role of His22 and His51 in oligomerization, three mutants were generated: H22A, H51A and H22AH51A mutants. The association state was examined by various gel electrophoresis systems (SDS, PFO and BN PAGE), and AUC-SE in C14SB micelles. Results showed that wild type formed pentamer in C14SB shown by blue native PAGE and AUC. H22A mutation destabilized the pentameric structure while H51A mutation did not affect it much. Investigation of the secondary structure of SH proteins reconstituted in DMPC by ATR-FTIR showed that all three mutants altered the composition of secondary structures and H51A mutation extended the region of non-exchangeable residues. Therefore, His22 is crucial in oligomer formation while His51 affects the orientation of SH protein, and both histidines affect the secondary structure of SH proteins.