RESUMEN
Long tail fibers of bacteriophage T4 are formed by proteins gp34, gp35, gp36, and gp37, with gp34 located at the phage-proximal end and gp37 at the phage-distal, receptor-binding end. We have solved the structure of the carboxy-terminal region of gp34, consisting of amino acids 894-1289, by single-wavelength anomalous diffraction and extended the structure to amino acids 744-1289 using data collected from crystals containing longer gp34-fragments. The structure reveals three repeats of a mixed α-ß fibrous domain in residues 744 to 877. A triple-helical neck connects to an extended triple ß-helix domain (amino acids 900-1127) punctuated by two ß-prism domains. Next, a ß-prism domain decorated with short helices and extended ß-helices is present (residues 1146-1238), while the C-terminal end is capped with another short ß-helical region and three ß-hairpins. The structure provides insight into the stability of the fibrous gp34 protein.
Asunto(s)
Bacteriófago T4/química , Proteínas de la Cola de los Virus/química , Cristalografía por Rayos X , Modelos Moleculares , Conformación ProteicaRESUMEN
The phage-proximal part of the long tail fibres of bacteriophage T4 consists of a trimer of the 1289 amino-acid gene product 34 (gp34). Different carboxy-terminal parts of gp34 have been produced and crystallized. Crystals of gp34(726-1289) diffracting X-rays to 2.9â Å resolution, crystals of gp34(781-1289) diffracting to 1.9â Å resolution and crystals of gp34(894-1289) diffracting to 3.0 and 2.0â Å resolution and belonging to different crystal forms were obtained. Native data were collected for gp34(726-1289) and gp34(894-1289), while single-wavelength anomalous diffraction data were collected for selenomethionine-containing gp34(781-1289) and gp34(894-1289). For the latter, high-quality anomalous signal was obtained.