[Back to Number 11 ToC] [Back to Journal Contents] [Back to Biokhimiya Home page]
[View Full Article] [Download Reprint (PDF)]

Structure and Folding of Bacteriophage T4 Gene Product 9 Triggering Infection. I. Production and Properties of Recombinant Protein

G. A. Navruzbekov1, L. P. Kurochkina1*, V. A. Kostyuchenko1, T. G. Zurabishvili2, S. Y. Venyaminov3, and V. V. Mesyanzhinov1

1Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, Moscow, 117871 Russia; fax: (095) 336-6022; E-mail: vvm@ibch.siobc.ras.ru

2Ivanovskii Institute of Virology, Russian Academy of Medical Sciences, ul. Gamalei 16, Moscow, 123098 Russia

3Department of Biochemistry and Molecular Biology, Mayo Foundation, 200 First Street SW, Rochester, Minnesota, 55905, USA

* To whom correspondence should be addressed.

Received July 15, 1999
Gene product 9 (gp9, 288 amino acid residues per monomer, molecular weight 30.7 kD) of bacteriophage T4 triggers the baseplate reorganization and the sheath contraction after interaction of the long tail fibers with the receptors of the bacterial cell. In this work we have produced the recombinant protein and determined that gp9 is a stable homotrimer and active in in vitro complementation assay completing the defective phage particles which lack gp9. According to CD-spectroscopy data, the gp9 polypeptide chain contains 65-73% beta-structure and 11-16% alpha-helical segments, this being in good agreement with secondary structure prediction results. Additionally, we have constructed a set of plasmid vectors for expression of gp9 deletion mutants. The fragments with consecutive truncations of the N-terminus of the molecule, as well as the full-length protein, are trimers resistant to SDS treatment and decrease infective phage particle formation in in vitro complementation assay with native gp9. The deletion of the molecule C-terminal region results in failure of trimerization and decreases the stability of the protein.
KEY WORDS: bacteriophage T4, gene product 9, expression vector