title: Structure of the 3.3MDa, in vitro assembled, hubless bacteriophage T4 baseplate.
abstract: The bacteriophage T4 baseplate is the control center of the virus, where the recognition of an Escherichiacoli host by the long tail fibers is translated into a signal to initiate infection. The short tail fibers unfold from the baseplate for firm attachment to the host, followed by shrinkage of the tail sheath that causes the tail tube to enter and cross the periplasmic space ending with injection of the genome into the host. During this process, the 6.5MDa baseplate changes its structure from a "dome" shape to a "star" shape. An in vitro assembled hubless baseplate has been crystallized. It consists of six copies of the recombinantly expressed trimeric gene product (gp) 10, monomeric gp7, dimeric gp8, dimeric gp6 and monomeric gp53. The diffraction pattern extends, at most, to 4.0Å resolution. The known partial structures of gp10, gp8, and gp6 and their relative position in the baseplate derived from earlier electron microscopy studies were used for molecular replacement. An electron density map has been calculated based on molecular replacement, single isomorphous replacement with anomalous dispersion data and 2-fold non-crystallographic symmetry averaging between two baseplate wedges in the crystallographic asymmetric unit. The current electron density map indicates that there are structural changes in the gp6, gp8, and gp10 oligomers compared to their structures when separately crystallized. Additional density is also visible corresponding to gp7, gp53 and the unknown parts of gp10 and gp6.
authors.affiliation: Department of Biological Sciences, Purdue University, 240 S. Martin Jischke Drive, West Lafayette, IN 47907-2032, USA.
authors.forename: Moh Lan
authors.initials: ML
authors.lastname: Yap
authors.affiliation: Department of Biological Sciences, Purdue University, 240 S. Martin Jischke Drive, West Lafayette, IN 47907-2032, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Klose
authors.affiliation: Department of Biological Sciences, Purdue University, 240 S. Martin Jischke Drive, West Lafayette, IN 47907-2032, USA.
authors.forename: Pavel
authors.initials: P
authors.lastname: Plevka
authors.affiliation: Department of Biological Sciences, Purdue University, 240 S. Martin Jischke Drive, West Lafayette, IN 47907-2032, USA.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Aksyuk
authors.affiliation: Department of Biological Sciences, Purdue University, 240 S. Martin Jischke Drive, West Lafayette, IN 47907-2032, USA.
authors.forename: Xinzheng
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Life Science, Tokyo Institute of Technology, 4259 Midori-ku, Nagatsuta, Yokohama 226-8501, Japan.
authors.forename: Fumio
authors.initials: F
authors.lastname: Arisaka
authors.affiliation: Department of Biological Sciences, Purdue University, 240 S. Martin Jischke Drive, West Lafayette, IN 47907-2032, USA. Electronic address: mr@purdue.edu.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Rossmann
mesh_terms: D017122:Bacteriophage T4 / Q000737:chemistry* / Q000235:genetics; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000235:genetics; D006023:Glycoproteins / Q000737:chemistry* / Q000235:genetics; D011487:Protein Conformation; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics; D014771:Virion / Q000737:chemistry / Q000235:genetics
chemical_list: D006023:Glycoproteins; D014764:Viral Proteins; C435064:glycoprotein 8, bacteriophage T4
keywords: Bacteriophage T4; Baseplate; Low resolution; X-ray crystallography